<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>1. What is Blockchain Technology?</b></td>

</tr>

<tr>

<td>A) A centralized ledger system</td>

</tr>

<tr>

<td>B) A distributed and decentralized ledger system</td>

</tr>

<tr>

<td>C) A payment gateway</td>

</tr>

<tr>

<td>D) A data storage service</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>2. Which of the following is a key feature of blockchain?</b></td>

<tr>

<td>A) Reversible transactions</td>

</tr>

<tr>

<td>B) Centralized control</td>

</tr>

<tr>

<td>C) Immutability and transparency</td>

</tr>

<tr>

<td>D) Proprietary technology</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>3. What is the primary purpose of a consensus mechanism in blockchain?</b></td>

</tr>

<tr>

<td>A) To enable centralized control</td>

</tr>
<tr>

<td>B) To ensure all nodes agree on the validity of transactions</td>

</tr>

<tr>

<td>C) To encrypt data</td>

</tr>

<tr>

<td>D) To reduce transaction costs</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>4. Which consensus algorithm is used in Bitcoin?</b></td>

</tr>

<tr>

<td>A) Proof of Stake (PoS)</td>

</tr>

<tr>

<td>B) Proof of Work (PoW)</td>

</tr>

<tr>
<td>C) Delegated Proof of Stake (DPoS)</td>

</tr>

<tr>

<td>D) Practical Byzantine Fault Tolerance (PBFT)</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>5. What is a smart contract?</b></td>

</tr>

<tr>

<td>A) A traditional paper-based contract</td>

</tr>

<tr>

<td>B) A digital agreement that automatically executes when conditions are met</td>

</tr>

<tr>

<td>C) A contract written in legal language</td>

</tr>

<tr>

<td>D) An encrypted document</td>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>6. Which programming language is primarily used to write Ethereum smart contracts?</b></td>

</tr>

<tr>

<td>A) Python</td>

</tr>

<tr>

<td>B) Solidity</td>

</tr>

<tr>

<td>C) JavaScript</td>

</tr>

<tr>

<td>D) C++</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>7. What is the primary function of a node in a blockchain network?</b></td>

</tr>

<tr>

<td>A) To act as a central authority</td>

</tr>

<tr>

<td>B) To verify and validate transactions</td>

</tr>

<tr>

<td>C) To generate random numbers</td>

</tr>

<tr>

<td>D) To encrypt data</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>8. What is the purpose of a hash function in blockchain?</b></td>

</tr>

<tr>

<td>A) To encrypt data</td>

</tr>

<tr>

<td>B) To compress data</td>

</tr>

<tr>

<td>C) To convert input data into a fixed-size output</td>

</tr>

<tr>

<td>D) To delete old blocks</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>9. Which cryptographic algorithm is commonly used for digital signatures in blockchain?</b></td>

</tr>

<tr>

<td>A) RSA</td>
</tr>

<tr>

<td>B) SHA-256</td>

</tr>

<tr>

<td>C) Elliptic Curve Digital Signature Algorithm (ECDSA)</td>

</tr>

<tr>

<td>D) MD5</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>10. What does a blockchain block typically contain?</b></td>

</tr>

<tr>

<td>A) Only transaction data</td>

</tr>

<tr>

<td>B) A timestamp, transaction data, and a hash of the previous block</td>

</tr>
<tr>

<td>C) User credentials and passwords</td>

</tr>

<tr>

<td>D) Random numbers</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>11. What is a public key in blockchain cryptography?</b></td>

</tr>

<tr>

<td>A) A private, secret key used for decryption</td>

</tr>

<tr>

<td>B) A key that is shared publicly to verify digital signatures</td>

</tr>

<tr>

<td>C) A key used to encrypt data without decryption</td>

</tr>

<tr>

<td>D) A random number generated by miners</td>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>12. What is the role of miners in a blockchain network?</b></td>

</tr>

<tr>

<td>A) To store private keys</td>

</tr>

<tr>

<td>B) To create and validate new blocks by solving complex puzzles</td>

</tr>

<tr>

<td>C) To manage smart contracts</td>

</tr>

<tr>

<td>D) To encrypt all blockchain data</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>13. What is the purpose of a Merkle tree in blockchain?</b></td>

</tr>

<tr>

<td>A) To store usernames and passwords</td>

</tr>

<tr>

<td>B) To structure and verify data efficiently</td>

</tr>

<tr>

<td>C) To hash transactions into a block header</td>

</tr>

<tr>

<td>D) To increase block size</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>14. Which of the following best describes a private blockchain?</b></td>

</tr>

<tr>

<td>A) A blockchain that anyone can join and participate in</td>

</tr>

<tr>

<td>B) A blockchain restricted to a specific group of participants</td>

</tr>

<tr>

<td>C) A blockchain that only stores financial transactions</td>

</tr>

<tr>

<td>D) A blockchain used exclusively for cryptocurrencies</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>15. What is a cryptocurrency wallet?</b></td>

</tr>

<tr>

<td>A) A digital file used to store private keys and manage transactions</td>
</tr>

<tr>

<td>B) A physical device used to mine cryptocurrencies</td>

</tr>

<tr>

<td>C) A database that stores blockchain transactions</td>

</tr>

<tr>

<td>D) A smart contract used for payments</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>16. What is a token in blockchain terminology?</b></td>

</tr>

<tr>

<td>A) A cryptocurrency with no value</td>

</tr>

<tr>

<td>B) A digital asset that can represent real-world or virtual items</td>

</tr>
<tr>

<td>C) A public key used in cryptography</td>

</tr>

<tr>

<td>D) A hash function</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>17. What does the term “gas” refer to in Ethereum?</b></td>

</tr>

<tr>

<td>A) The fuel used to mine blocks</td>

</tr>

<tr>

<td>B) The cost required to execute a transaction or smart contract</td>

</tr>

<tr>

<td>C) The name of a consensus algorithm</td>

</tr>

<tr>
<td>D) The hashing algorithm used in Ethereum</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>18. Which type of blockchain allows anyone to read and submit transactions?</b></td>

</tr>

<tr>

<td>A) Private blockchain</td>

</tr>

<tr>

<td>B) Consortium blockchain</td>

</tr>

<tr>

<td>C) Public blockchain</td>

</tr>

<tr>

<td>D) Permissioned blockchain</td>

</tr>

<tr>

<td>Correct answer: C</td>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>19. What is the purpose of a decentralized application (DApp)?</b></td>

</tr>

<tr>

<td>A) To store blockchain data centrally</td>

</tr>

<tr>

<td>B) To run on a centralized server</td>

</tr>

<tr>

<td>C) To operate autonomously without central control</td>

</tr>

<tr>

<td>D) To encrypt transactions</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>20. What is the function of a block header in a blockchain?</b></td>

</tr>

<tr>

<td>A) To store all the transactions of the block</td>

</tr>

<tr>

<td>B) To link blocks and ensure data integrity</td>

</tr>

<tr>

<td>C) To hash the entire blockchain</td>

</tr>

<tr>

<td>D) To serve as a wallet address</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>21. What is the main purpose of a consensus algorithm in blockchain?</b></td>

</tr>

<tr>

<td>A) To increase the speed of transactions</td>

<tr>

<td>B) To ensure all nodes agree on the current state of the ledger</td>

</tr>

<tr>

<td>C) To reduce energy consumption</td>

</tr>

<tr>

<td>D) To create new cryptocurrencies</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>22. What is a smart contract?</b></td>

</tr>

<tr>

<td>A) A legally binding contract</td>

</tr>

<tr>

<td>B) A self-executing contract with predefined rules</td>

</tr>
<tr>

<td>C) A contract stored in a physical vault</td>

</tr>

<tr>

<td>D) A digital key used in cryptography</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>23. What is a fork in blockchain?</b></td>

</tr>

<tr>

<td>A) A software update that introduces backward compatibility</td>

</tr>

<tr>

<td>B) A divergence in the blockchain that creates two separate paths</td>

</tr>

<tr>

<td>C) A process for mining new blocks</td>

</tr>

<tr>
<td>D) A type of encryption method</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>24. What does Proof of Stake (PoS) rely on for block validation?</b></td>

</tr>

<tr>

<td>A) Computational power</td>

</tr>

<tr>

<td>B) Stakeholders’ ownership of cryptocurrency</td>

</tr>

<tr>

<td>C) Random numbers</td>

</tr>

<tr>

<td>D) Centralized servers</td>

</tr>

<tr>

<td>Correct answer: B</td>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>25. What is a hash function in blockchain?</b></td>

</tr>

<tr>

<td>A) A method to store blocks sequentially</td>

</tr>

<tr>

<td>B) A mathematical function that converts data into a fixed-size output</td>

</tr>

<tr>

<td>C) A process used to connect smart contracts</td>

</tr>

<tr>

<td>D) A consensus algorithm</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>26. What is the purpose of a nonce in a blockchain block?</b></td>

</tr>

<tr>

<td>A) To identify the block creator</td>

</tr>

<tr>

<td>B) To track transaction fees</td>

</tr>

<tr>

<td>C) To alter the hash of the block during mining</td>

</tr>

<tr>

<td>D) To store transaction details</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>27. What is the role of digital signatures in blockchain?</b></td>

</tr>

<tr>
<td>A) To encrypt the entire blockchain</td>

</tr>

<tr>

<td>B) To verify the authenticity and integrity of transactions</td>

</tr>

<tr>

<td>C) To mine new blocks</td>

</tr>

<tr>

<td>D) To store wallet addresses</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>28. What is the difference between a coin and a token?</b></td>

</tr>

<tr>

<td>A) Coins are physical, and tokens are digital</td>

</tr>

<tr>

<td>B) Coins have their own blockchain, while tokens are built on existing blockchains</td>
</tr>

<tr>

<td>C) Tokens are used only for smart contracts</td>

</tr>

<tr>

<td>D) Coins are always more valuable than tokens</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>29. What is a decentralized exchange (DEX)?</b></td>

</tr>

<tr>

<td>A) A platform controlled by a central authority</td>

</tr>

<tr>

<td>B) A peer-to-peer marketplace for cryptocurrency trading</td>

</tr>

<tr>

<td>C) A mining pool for cryptocurrency</td>

</tr>
<tr>

<td>D) A physical store for cryptocurrency</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>30. Which blockchain platform is most known for its smart contract functionality?</b></td>

</tr>

<tr>

<td>A) Bitcoin</td>

</tr>

<tr>

<td>B) Ethereum</td>

</tr>

<tr>

<td>C) Ripple</td>

</tr>

<tr>

<td>D) Litecoin</td>

</tr>

<tr>
<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>31. What is a 51% attack?</b></td>

</tr>

<tr>

<td>A) An attack that occurs when miners take a break</td>

</tr>

<tr>

<td>B) A scenario where a group controls more than half of the blockchain's mining power</td>

</tr>

<tr>

<td>C) A smart contract vulnerability</td>

</tr>

<tr>

<td>D) A type of cryptographic function</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>
<td></td></tr><tr><td class="questiontableheader"><br/>

<b>32. What is a permissioned blockchain?</b></td>

</tr>

<tr>

<td>A) A blockchain that anyone can join and participate in</td>

</tr>

<tr>

<td>B) A blockchain restricted to specific participants</td>

</tr>

<tr>

<td>C) A blockchain that only stores financial transactions</td>

</tr>

<tr>

<td>D) A type of DApp</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>33. What is the primary purpose of decentralized identity in blockchain?</b></td>

</tr>
<tr>

<td>A) To create anonymous transactions</td>

</tr>

<tr>

<td>B) To give users control over their personal data</td>

</tr>

<tr>

<td>C) To increase mining speed</td>

</tr>

<tr>

<td>D) To develop new cryptocurrencies</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>34. What is the role of an Initial Coin Offering (ICO)?</b></td>

</tr>

<tr>

<td>A) To mine new blocks</td>

</tr>

<tr>
<td>B) To raise funds for a blockchain project</td>

</tr>

<tr>

<td>C) To store digital signatures</td>

</tr>

<tr>

<td>D) To upgrade blockchain algorithms</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>35. What is the function of a blockchain node?</b></td>

</tr>

<tr>

<td>A) To encrypt transactions</td>

</tr>

<tr>

<td>B) To participate in the network by validating transactions</td>

</tr>

<tr>

<td>C) To mine new cryptocurrencies</td>

<tr>

<td>D) To create smart contracts</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>36. What is a Distributed Ledger Technology (DLT)?</b></td>

</tr>

<tr>

<td>A) A centralized system for recording transactions</td>

</tr>

<tr>

<td>B) A decentralized database managed by multiple participants</td>

</tr>

<tr>

<td>C) A cryptographic algorithm</td>

</tr>

<tr>

<td>D) A hardware wallet</td>

</tr>

<tr>
<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>37. What is the function of gas in the Ethereum network?</b></td>

</tr>

<tr>

<td>A) It powers the hardware running the blockchain</td>

</tr>

<tr>

<td>B) It measures the computational work required for transactions</td>

</tr>

<tr>

<td>C) It secures digital wallets</td>

</tr>

<tr>

<td>D) It is used to mine new blocks</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>
<td></td></tr><tr><td class="questiontableheader"><br/>

<b>38. What is a private key in blockchain?</b></td>

</tr>

<tr>

<td>A) A public address used to receive cryptocurrency</td>

</tr>

<tr>

<td>B) A unique cryptographic key used to authorize transactions</td>

</tr>

<tr>

<td>C) A method for encrypting blocks</td>

</tr>

<tr>

<td>D) A tool for mining cryptocurrencies</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>39. What is a hot wallet?</b></td>

</tr>
<tr>

<td>A) A wallet connected to the internet</td>

</tr>

<tr>

<td>B) A wallet made of physical materials</td>

</tr>

<tr>

<td>C) A highly secure offline wallet</td>

</tr>

<tr>

<td>D) A hardware device for mining</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>40. What is the difference between a public and private blockchain?</b></td>

</tr>

<tr>

<td>A) Public blockchains are always faster</td>

</tr>

<tr>
<td>B) Private blockchains are controlled by a specific group</td>

</tr>

<tr>

<td>C) Public blockchains use different hashing algorithms</td>

</tr>

<tr>

<td>D) Private blockchains cannot store transactions</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>41. What is a zero-knowledge proof in blockchain?</b></td>

</tr>

<tr>

<td>A) A way to mine cryptocurrency without using energy</td>

</tr>

<tr>

<td>B) A cryptographic method to prove knowledge without revealing data</td>

</tr>

<tr>

<td>C) A type of consensus algorithm</td>

<tr>

<td>D) A tool for creating smart contracts</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>42. What is the main purpose of a blockchain explorer?</b></td>

</tr>

<tr>

<td>A) To mine new blocks</td>

</tr>

<tr>

<td>B) To track and view transactions on the blockchain</td>

</tr>

<tr>

<td>C) To encrypt data on the blockchain</td>

</tr>

<tr>

<td>D) To validate nodes</td>

</tr>
<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>43. What is a peer-to-peer network in blockchain?</b></td>

</tr>

<tr>

<td>A) A network with a central server</td>

</tr>

<tr>

<td>B) A decentralized network of interconnected nodes</td>

</tr>

<tr>

<td>C) A mining pool</td>

</tr>

<tr>

<td>D) A type of encryption method</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>44. What is tokenization in blockchain?</b></td>

</tr>

<tr>

<td>A) Creating a new blockchain</td>

</tr>

<tr>

<td>B) Converting real-world assets into digital tokens</td>

</tr>

<tr>

<td>C) Encrypting blockchain nodes</td>

</tr>

<tr>

<td>D) Storing cryptocurrency in a wallet</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>45. What is an oracle in blockchain?</b></td>

<tr>

<td>A) A database system</td>

</tr>

<tr>

<td>B) A service that provides external data to smart contracts</td>

</tr>

<tr>

<td>C) A type of wallet</td>

</tr>

<tr>

<td>D) A consensus algorithm</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>46. What is a multi-signature wallet?</b></td>

</tr>

<tr>

<td>A) A wallet that requires one signature for transactions</td>

</tr>
<tr>

<td>B) A wallet that requires multiple signatures to authorize transactions</td>

</tr>

<tr>

<td>C) A wallet used only for staking</td>

</tr>

<tr>

<td>D) A wallet with no encryption</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>47. What is the purpose of sharding in blockchain?</b></td>

</tr>

<tr>

<td>A) To secure the network</td>

</tr>

<tr>

<td>B) To increase scalability by splitting the blockchain into smaller parts</td>

</tr>

<tr>
<td>C) To encrypt blocks</td>

</tr>

<tr>

<td>D) To reduce transaction fees</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>48. What is a DAO (Decentralized Autonomous Organization)?</b></td>

</tr>

<tr>

<td>A) A physical company that mines cryptocurrency</td>

</tr>

<tr>

<td>B) An organization governed by smart contracts on a blockchain</td>

</tr>

<tr>

<td>C) A tool for encrypting transactions</td>

</tr>

<tr>

<td>D) A government entity</td>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>49. What is the purpose of a Merkle Tree in blockchain?</b></td>

</tr>

<tr>

<td>A) To reduce transaction fees</td>

</tr>

<tr>

<td>B) To efficiently verify the integrity of transactions</td>

</tr>

<tr>

<td>C) To mine new blocks</td>

</tr>

<tr>

<td>D) To create smart contracts</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>50. What is a sidechain in blockchain technology?</b></td>

</tr>

<tr>

<td>A) A secondary blockchain that runs in parallel to the main chain</td>

</tr>

<tr>

<td>B) A tool for encrypting transactions</td>

</tr>

<tr>

<td>C) A way to mine cryptocurrency</td>

</tr>

<tr>

<td>D) A method to create smart contracts</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>51. What is the primary benefit of using smart contracts in blockchain?</b></td>

<tr>

<td>A) They eliminate the need for intermediaries</td>

</tr>

<tr>

<td>B) They increase transaction fees</td>

</tr>

<tr>

<td>C) They require manual execution</td>

</tr>

<tr>

<td>D) They are only used in Bitcoin</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>52. What does the term “mining” refer to in blockchain?</b></td>

</tr>

<tr>

<td>A) Extracting data from blocks</td>

</tr>
<tr>

<td>B) Validating and adding transactions to the blockchain</td>

</tr>

<tr>

<td>C) Storing cryptocurrencies</td>

</tr>

<tr>

<td>D) Encrypting private keys</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>53. What is a blockchain fork?</b></td>

</tr>

<tr>

<td>A) A new cryptocurrency created from scratch</td>

</tr>

<tr>

<td>B) A split in the blockchain that creates two versions</td>

</tr>

<tr>
<td>C) A method of encrypting blocks</td>

</tr>

<tr>

<td>D) A type of digital wallet</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>54. What is a hash function in blockchain?</b></td>

</tr>

<tr>

<td>A) A function that compresses data into a fixed-length output</td>

</tr>

<tr>

<td>B) A tool for mining cryptocurrencies</td>

</tr>

<tr>

<td>C) A method of creating new blocks</td>

</tr>

<tr>

<td>D) A wallet security feature</td>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>55. What is the primary purpose of consensus algorithms in blockchain?</b></td>

</tr>

<tr>

<td>A) To encrypt data</td>

</tr>

<tr>

<td>B) To achieve agreement on the state of the blockchain</td>

</tr>

<tr>

<td>C) To create new wallets</td>

</tr>

<tr>

<td>D) To transfer tokens</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>56. What is Proof of Work (PoW)?</b></td>

</tr>

<tr>

<td>A) A consensus algorithm requiring miners to solve complex problems</td>

</tr>

<tr>

<td>B) A method of creating new wallets</td>

</tr>

<tr>

<td>C) A tool for tracking transactions</td>

</tr>

<tr>

<td>D) A cryptographic function for encrypting data</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>57. What is a node in blockchain?</b></td>

</tr>

<tr>

<td>A) A mining tool</td>

</tr>

<tr>

<td>B) A device that stores a copy of the blockchain</td>

</tr>

<tr>

<td>C) A digital wallet</td>

</tr>

<tr>

<td>D) A smart contract</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>58. What is a public blockchain?</b></td>

</tr>

<tr>

<td>A) A blockchain with restricted access</td>

<tr>

<td>B) A blockchain open to everyone to participate</td>

</tr>

<tr>

<td>C) A blockchain for government use only</td>

</tr>

<tr>

<td>D) A private blockchain</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>59. What is an Initial Coin Offering (ICO)?</b></td>

</tr>

<tr>

<td>A) A fundraising method using cryptocurrency tokens</td>

</tr>

<tr>

<td>B) A process of encrypting wallets</td>

</tr>
<tr>

<td>C) A mining technique</td>

</tr>

<tr>

<td>D) A type of consensus algorithm</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>60. What is a hybrid blockchain?</b></td>

</tr>

<tr>

<td>A) A combination of public and private blockchains</td>

</tr>

<tr>

<td>B) A new consensus algorithm</td>

</tr>

<tr>

<td>C) A type of mining pool</td>

</tr>

<tr>
<td>D) A method of encrypting data</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>61. What is the difference between fungible and non-fungible tokens?</b></td>

</tr>

<tr>

<td>A) Fungible tokens are unique, non-fungible tokens are identical</td>

</tr>

<tr>

<td>B) Fungible tokens are interchangeable, non-fungible tokens are unique</td>

</tr>

<tr>

<td>C) Both are the same</td>

</tr>

<tr>

<td>D) Fungible tokens are not used in blockchain</td>

</tr>

<tr>

<td>Correct answer: B</td>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>62. What is Proof of Stake (PoS)?</b></td>

</tr>

<tr>

<td>A) A consensus mechanism based on mining power</td>

</tr>

<tr>

<td>B) A consensus mechanism where validators are chosen based on their stake</td>

</tr>

<tr>

<td>C) A method for creating wallets</td>

</tr>

<tr>

<td>D) A cryptographic hash function</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>63. What is a dApp (decentralized application)?</b></td>

</tr>

<tr>

<td>A) An application that runs on a central server</td>

</tr>

<tr>

<td>B) An application that runs on a blockchain network</td>

</tr>

<tr>

<td>C) A wallet security feature</td>

</tr>

<tr>

<td>D) A tool for mining cryptocurrencies</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>64. What is a crypto wallet?</b></td>

</tr>

<tr>
<td>A) A physical wallet for storing cash</td>

</tr>

<tr>

<td>B) A digital wallet for storing cryptocurrencies</td>

</tr>

<tr>

<td>C) A tool for mining blocks</td>

</tr>

<tr>

<td>D) A blockchain explorer</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>65. What is a blockchain transaction?</b></td>

</tr>

<tr>

<td>A) A method to store cryptocurrency</td>

</tr>

<tr>

<td>B) A record of a transfer of digital assets</td>

<tr>

<td>C) A tool for encrypting data</td>

</tr>

<tr>

<td>D) A type of wallet</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>66. What is a hash rate in blockchain?</b></td>

</tr>

<tr>

<td>A) The speed at which transactions are confirmed</td>

</tr>

<tr>

<td>B) The speed at which a miner can solve cryptographic puzzles</td>

</tr>

<tr>

<td>C) The size of a digital wallet</td>

</tr>
<tr>

<td>D) The security level of a blockchain</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>67. What is a block in blockchain?</b></td>

</tr>

<tr>

<td>A) A transaction fee</td>

</tr>

<tr>

<td>B) A record containing multiple transactions</td>

</tr>

<tr>

<td>C) A type of cryptocurrency</td>

</tr>

<tr>

<td>D) A tool for creating smart contracts</td>

</tr>

<tr>
<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>68. What is Ethereum?</b></td>

</tr>

<tr>

<td>A) A cryptocurrency</td>

</tr>

<tr>

<td>B) A blockchain platform that supports smart contracts</td>

</tr>

<tr>

<td>C) A wallet provider</td>

</tr>

<tr>

<td>D) A mining pool</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>
<td></td></tr><tr><td class="questiontableheader"><br/>

<b>69. What is a decentralized ledger?</b></td>

</tr>

<tr>

<td>A) A traditional bank ledger</td>

</tr>

<tr>

<td>B) A distributed database that is not controlled by a central authority</td>

</tr>

<tr>

<td>C) A wallet security feature</td>

</tr>

<tr>

<td>D) A type of encryption</td>

</tr>

<tr><td>Correct answer: B</td>

</tr>

<tr><td></td></tr><tr><td class="questiontableheader"><br/>

<b>70. What is a token in blockchain?</b></td>

</tr>

<tr><td>A) A digital representation of an asset</td>

</tr>
<tr><td>B) A physical coin</td>

</tr>

<tr><td>C) A type of encryption</td>

</tr>

<tr><td>D) A smart contract</td>

</tr><tr><td>Correct answer: A</td></tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>71. What is the primary function of a consensus algorithm in blockchain technology?</b></td>

</tr>

<tr>

<td>A) To encrypt transaction data</td>

</tr>

<tr>

<td>B) To ensure all nodes agree on the ledger's state</td>

</tr>

<tr>

<td>C) To create new digital currencies</td>

</tr>

<tr>

<td>D) To manage user identities</td>

</tr>

<tr>

<td>Correct answer: B</td>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>72. Which of the following is a characteristic of a decentralized system?</b></td>

</tr>

<tr>

<td>A) Central authority controls all data</td>

</tr>

<tr>

<td>B) Single point of failure</td>

</tr>

<tr>

<td>C) Peer-to-peer network structure</td>

</tr>

<tr>

<td>D) Limited scalability</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>73. What role do hash functions play in blockchain technology?</b></td>

</tr>

<tr>

<td>A) Encrypting user passwords</td>

</tr>

<tr>

<td>B) Compressing blockchain data</td>

</tr>

<tr>

<td>C) Generating unique identifiers for data blocks</td>

</tr>

<tr>

<td>D) Managing network traffic</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>74. In blockchain, what is a 'block'?</b></td>

</tr>

<tr>
<td>A) A single transaction record</td>

</tr>

<tr>

<td>B) A collection of transaction records</td>

</tr>

<tr>

<td>C) A user's digital wallet</td>

</tr>

<tr>

<td>D) A node in the network</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>75. What is the purpose of a digital signature in blockchain transactions?</b></td>

</tr>

<tr>

<td>A) To encrypt the transaction data</td>

</tr>

<tr>

<td>B) To verify the sender's identity and ensure data integrity</td>

<tr>

<td>C) To generate new blocks</td>

</tr>

<tr>

<td>D) To manage consensus among nodes</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>76. Which consensus mechanism relies on validators' stake in the network?</b></td>

</tr>

<tr>

<td>A) Proof of Work (PoW)</td>

</tr>

<tr>

<td>B) Proof of Stake (PoS)</td>

</tr>

<tr>

<td>C) Delegated Proof of Stake (DPoS)</td>

</tr>
<tr>

<td>D) Practical Byzantine Fault Tolerance (PBFT)</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>77. What distinguishes a public blockchain from a private blockchain?</b></td>

</tr>

<tr>

<td>A) Public blockchains are faster</td>

</tr>

<tr>

<td>B) Private blockchains are open to anyone</td>

</tr>

<tr>

<td>C) Public blockchains are permissionless</td>

</tr>

<tr>

<td>D) Private blockchains use cryptocurrency</td>

</tr>

<tr>
<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>78. What is a 'smart contract' in the context of blockchain?</b></td>

</tr>

<tr>

<td>A) A legal agreement between two parties</td>

</tr>

<tr>

<td>B) A self-executing contract with terms directly written into code</td>

</tr>

<tr>

<td>C) A digital certificate for user authentication</td>

</tr>

<tr>

<td>D) A protocol for network communication</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>
<td></td></tr><tr><td class="questiontableheader"><br/>

<b>79. How does blockchain ensure the immutability of data?</b></td>

</tr>

<tr>

<td>A) Through centralized data storage</td>

</tr>

<tr>

<td>B) By using cryptographic hashes and consensus mechanisms</td>

</tr>

<tr>

<td>C) By limiting the number of nodes</td>

</tr>

<tr>

<td>D) Through regular data backups</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>80. What is the primary advantage of using a decentralized application (dApp)?</b></td>

</tr>
<tr>

<td>A) Centralized control</td>

</tr>

<tr>

<td>B) Enhanced security and transparency</td>

</tr>

<tr>

<td>C) Faster transaction speeds</td>

</tr>

<tr>

<td>D) Lower development costs</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>81. In blockchain, what is a 'node'?</b></td>

</tr>

<tr>

<td>A) A user of the blockchain</td>

</tr>

<tr>
<td>B) A device that maintains a copy of the blockchain and participates in the network</td>

</tr>

<tr>

<td>C) A transaction validator</td>

</tr>

<tr>

<td>D) A miner's computer</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>82. What is the role of cryptography in blockchain technology?</b></td>

</tr>

<tr>

<td>A) To speed up transactions</td>

</tr>

<tr>

<td>B) To secure data and ensure privacy</td>

</tr>

<tr>

<td>C) To create new cryptocurrencies</td>

<tr>

<td>D) To manage network traffic</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>83. What does 'DLT' stand for in the context of blockchain?</b></td>

</tr>

<tr>

<td>A) Decentralized Ledger Technology</td>

</tr>

<tr>

<td>B) Distributed Ledger Technology</td>

</tr>

<tr>

<td>C) Digital Ledger Token</td>

</tr>

<tr>

<td>D) Dynamic Ledger Transfer</td>

</tr>
<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>84. Which type of blockchain allows only specific participants to join the network?</b></td>

</tr>

<tr>

<td>A) Public blockchain</td>

</tr>

<tr>

<td>B) Private blockchain</td>

</tr>

<tr>

<td>C) Hybrid blockchain</td>

</tr>

<tr>

<td>D) Consortium blockchain</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>85. What is a 'Merkle Tree' used for in blockchain?</b></td>

</tr>

<tr>

<td>A) To track the number of nodes in a network</td>

</tr>

<tr>

<td>B) To secure smart contracts</td>

</tr>

<tr>

<td>C) To efficiently verify the integrity of data blocks</td>

</tr>

<tr>

<td>D) To encrypt user data</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>86. What is the purpose of a genesis block in a blockchain?</b></td>

<tr>

<td>A) It serves as a backup block</td>

</tr>

<tr>

<td>B) It is the first block in the blockchain</td>

</tr>

<tr>

<td>C) It contains transaction fees</td>

</tr>

<tr>

<td>D) It is used to reset the network</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>87. What is the primary difference between a soft fork and a hard fork in blockchain?</b></td>

</tr>

<tr>

<td>A) Soft forks require consensus, while hard forks do not</td>

</tr>
<tr>

<td>B) Hard forks are backward-compatible, while soft forks are not</td>

</tr>

<tr>

<td>C) Soft forks are backward-compatible, while hard forks are not</td>

</tr>

<tr>

<td>D) Hard forks are temporary, while soft forks are permanent</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>88. Which blockchain platform introduced smart contracts?</b></td>

</tr>

<tr>

<td>A) Bitcoin</td>

</tr>

<tr>

<td>B) Ethereum</td>

</tr>

<tr>
<td>C) Ripple</td>

</tr>

<tr>

<td>D) Litecoin</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>89. In blockchain, what is a decentralized autonomous organization (DAO)?</b></td>

</tr>

<tr>

<td>A) A government agency that oversees blockchain networks</td>

</tr>

<tr>

<td>B) A centralized cryptocurrency exchange</td>

</tr>

<tr>

<td>C) A self-governing organization run by smart contracts</td>

</tr>

<tr>

<td>D) A group of miners</td>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>90. What is gas in the context of Ethereum?</b></td>

</tr>

<tr>

<td>A) The amount of storage a transaction uses</td>

</tr>

<tr>

<td>B) The fee required to perform a transaction or execute a smart contract</td>

</tr>

<tr>

<td>C) The energy consumption of a node</td>

</tr>

<tr>

<td>D) A new type of cryptocurrency</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>91. What is the primary function of a blockchain miner?</b></td>

</tr>

<tr>

<td>A) To store transaction data</td>

</tr>

<tr>

<td>B) To validate and add new blocks to the blockchain</td>

</tr>

<tr>

<td>C) To manage user identities</td>

</tr>

<tr>

<td>D) To create smart contracts</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>92. What is the significance of immutability in blockchain?</b></td>

</tr>

<tr>

<td>A) Data can be easily modified</td>

</tr>

<tr>

<td>B) Data remains unchanged once it is added to the blockchain</td>

</tr>

<tr>

<td>C) Data is encrypted</td>

</tr>

<tr>

<td>D) Data is decentralized</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>93. What is the main advantage of a permissioned blockchain?</b></td>

</tr>

<tr>

<td>A) Open to anyone</td>

<tr>

<td>B) Higher privacy and control</td>

</tr>

<tr>

<td>C) Requires no consensus</td>

</tr>

<tr>

<td>D) No need for security measures</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>94. In blockchain, what does decentralization help prevent?</b></td>

</tr>

<tr>

<td>A) Scalability</td>

</tr>

<tr>

<td>B) Single point of failure</td>

</tr>
<tr>

<td>C) Privacy breaches</td>

</tr>

<tr>

<td>D) Consensus issues</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>95. What is the double-spending problem in blockchain?</b></td>

</tr>

<tr>

<td>A) A user spends more than their balance</td>

</tr>

<tr>

<td>B) A transaction is processed twice</td>

</tr>

<tr>

<td>C) A cryptocurrency is spent multiple times</td>

</tr>

<tr>
<td>D) A block is mined twice</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>96. What is a fork in blockchain?</b></td>

</tr>

<tr>

<td>A) A temporary halt in transactions</td>

</tr>

<tr>

<td>B) A change to the blockchain's protocol</td>

</tr>

<tr>

<td>C) A new cryptocurrency</td>

</tr>

<tr>

<td>D) An error in the blockchain</td>

</tr>

<tr>

<td>Correct answer: B</td>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>97. What is the purpose of a block header in a blockchain?</b></td>

</tr>

<tr>

<td>A) To store transaction details</td>

</tr>

<tr>

<td>B) To link blocks together and ensure data integrity</td>

</tr>

<tr>

<td>C) To create new coins</td>

</tr>

<tr>

<td>D) To store user identities</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>98. How does blockchain achieve trustless transactions?</b></td>

</tr>

<tr>

<td>A) Through third-party intermediaries</td>

</tr>

<tr>

<td>B) Through decentralized consensus mechanisms</td>

</tr>

<tr>

<td>C) By encrypting all transactions</td>

</tr>

<tr>

<td>D) By limiting network participants</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>99. What is the role of cryptographic hashing in blockchain?</b></td>

</tr>

<tr>
<td>A) To encrypt user identities</td>

</tr>

<tr>

<td>B) To ensure data integrity and security</td>

</tr>

<tr>

<td>C) To mine new blocks</td>

</tr>

<tr>

<td>D) To link wallets together</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>100. Which of the following best describes blockchain scalability?</b></td>

</tr>

<tr>

<td>A) The ability to handle an increasing number of transactions per second</td>

</tr>

<tr>

<td>B) The ability to support multiple cryptocurrencies</td>

<tr>

<td>C) The ability to add more miners to the network</td>

</tr>

<tr>

<td>D) The ability to encrypt data on the blockchain</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>101. What is the primary function of Ethereum's Ethereum Virtual Machine (EVM)?</b></td>

</tr>

<tr>

<td>A) To execute smart contracts</td>

</tr>

<tr>

<td>B) To validate transactions on the blockchain</td>

</tr>

<tr>

<td>C) To mine cryptocurrency</td>

</tr>
<tr>

<td>D) To create decentralized applications</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>102. What is a smart contract on the Ethereum blockchain?</b></td>

</tr>

<tr>

<td>A) A contract written in physical paper that is stored digitally</td>

</tr>

<tr>

<td>B) A program that runs automatically when conditions are met</td>

</tr>

<tr>

<td>C) A set of rules for miners to follow during mining</td>

</tr>

<tr>

<td>D) A mechanism to store digital assets</td>

</tr>

<tr>
<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>103. Which of the following is a feature of Ethereum that differentiates it from Bitcoin?</b></td>

</tr>

<tr>

<td>A) Ethereum supports only cryptocurrency transactions</td>

</tr>

<tr>

<td>B) Ethereum has a built-in programming language to create smart contracts</td>

</tr>

<tr>

<td>C) Ethereum uses proof of work only</td>

</tr>

<tr>

<td>D) Ethereum transactions are not stored on the blockchain</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>
<td></td></tr><tr><td class="questiontableheader"><br/>

<b>104. What does the term 'gas' refer to in the Ethereum network?</b></td>

</tr>

<tr>

<td>A) The fee required to conduct a transaction or execute a smart contract</td>

</tr>

<tr>

<td>B) A type of cryptocurrency used on the Ethereum network</td>

</tr>

<tr>

<td>C) A function that ensures secure communication between nodes</td>

</tr>

<tr>

<td>D) The speed of processing a transaction</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>105. What is a Decentralized Autonomous Organization (DAO) on Ethereum?</b></td>

</tr>
<tr>

<td>A) A company that uses Ethereum's blockchain for business operations</td>

</tr>

<tr>

<td>B) A decentralized entity governed by smart contracts and tokens</td>

</tr>

<tr>

<td>C) A centralized management structure for blockchain technology</td>

</tr>

<tr>

<td>D) A type of cryptocurrency used for Ethereum transactions</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>106. Which consensus mechanism does Ethereum initially use for validating transactions?</b></td>

</tr>

<tr>

<td>A) Proof of Authority</td>

</tr>

<tr>
<td>B) Proof of Work</td>

</tr>

<tr>

<td>C) Proof of Stake</td>

</tr>

<tr>

<td>D) Delegated Proof of Stake</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>107. How are Ethereum miners rewarded for their efforts in the network?</b></td>

</tr>

<tr>

<td>A) They are paid in Ethereum gas tokens</td>

</tr>

<tr>

<td>B) They receive transaction fees and newly minted Ether (ETH)</td>

</tr>

<tr>

<td>C) They are rewarded with transaction confirmations</td>

<tr>

<td>D) They are paid a fixed salary</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>108. Which Ethereum feature allows the creation of decentralized applications (dApps)?</b></td>

</tr>

<tr>

<td>A) Smart contracts</td>

</tr>

<tr>

<td>B) Ethereum Wallet</td>

</tr>

<tr>

<td>C) Ethereum Explorer</td>

</tr>

<tr>

<td>D) Proof of Work</td>

</tr>
<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>109. What is the name of the Ethereum cryptocurrency?</b></td>

</tr>

<tr>

<td>A) Ether</td>

</tr>

<tr>

<td>B) Bitcoin</td>

</tr>

<tr>

<td>C) Ethereum Coin</td>

</tr>

<tr>

<td>D) Gas</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>110. What is a common use case for Ethereum's smart contracts?</b></td>

</tr>

<tr>

<td>A) Storing personal data</td>

</tr>

<tr>

<td>B) Creating and managing tokens</td>

</tr>

<tr>

<td>C) Recording personal banking information</td>

</tr>

<tr>

<td>D) Encrypting messages</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>111. What does the Ethereum protocol use to create a consensus in the network?</b></td>
</tr>

<tr>

<td>A) Hashing algorithms</td>

</tr>

<tr>

<td>B) Proof of Work and Proof of Stake</td>

</tr>

<tr>

<td>C) Transactions only</td>

</tr>

<tr>

<td>D) Digital signatures</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>112. What is the Ethereum Foundation's role in the Ethereum ecosystem?</b></td>

</tr>

<tr>

<td>A) It controls the price of Ether</td>

</tr>
<tr>

<td>B) It funds development and promotes Ethereum's global adoption</td>

</tr>

<tr>

<td>C) It manages Ethereum's consensus algorithm</td>

</tr>

<tr>

<td>D) It develops all Ethereum software</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>113. What does "Ethereum 2.0" refer to?</b></td>

</tr>

<tr>

<td>A) A new version of the Ethereum blockchain</td>

</tr>

<tr>

<td>B) The implementation of Proof of Stake to replace Proof of Work</td>

</tr>

<tr>
<td>C) A version of Ethereum for enterprise use</td>

</tr>

<tr>

<td>D) A new digital currency on the Ethereum blockchain</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>114. Which of the following is NOT a benefit of using Ethereum for decentralized
applications?</b></td>

</tr>

<tr>

<td>A) Transparency of transactions</td>

</tr>

<tr>

<td>B) High scalability of applications</td>

</tr>

<tr>

<td>C) Trustless execution of programs</td>

</tr>

<tr>

<td>D) Ability to operate without intermediaries</td>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>115. What is the purpose of Ethereum's "Solidity" programming language?</b></td>

</tr>

<tr>

<td>A) To create decentralized databases</td>

</tr>

<tr>

<td>B) To develop Ethereum-based applications and smart contracts</td>

</tr>

<tr>

<td>C) To develop other cryptocurrencies</td>

</tr>

<tr>

<td>D) To analyze transaction data</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>116. What is the key characteristic of decentralized applications (dApps) on the Ethereum platform?
</b></td>

</tr>

<tr>

<td>A) They are hosted on centralized servers</td>

</tr>

<tr>

<td>B) They run without a central authority, using smart contracts</td>

</tr>

<tr>

<td>C) They require centralized data storage</td>

</tr>

<tr>

<td>D) They do not use blockchain technology</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>117. What is the primary purpose of an Ethereum wallet?</b></td>

<tr>

<td>A) To store physical copies of Ether</td>

</tr>

<tr>

<td>B) To store and manage private keys, allowing interaction with the blockchain</td>

</tr>

<tr>

<td>C) To mine Ether</td>

</tr>

<tr>

<td>D) To provide a transaction fee discount</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>118. What is the role of a validator in the Ethereum Proof of Stake (PoS) system?</b></td>

</tr>

<tr>

<td>A) To validate transactions and create new blocks in exchange for rewards</td>

</tr>
<tr>

<td>B) To store and secure data on the Ethereum blockchain</td>

</tr>

<tr>

<td>C) To approve or reject smart contracts</td>

</tr>

<tr>

<td>D) To mine Ether in return for transaction fees</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>119. Which of the following is a key advantage of the Ethereum Proof of Stake (PoS) system over
Proof of Work (PoW)?</b></td>

</tr>

<tr>

<td>A) Lower energy consumption</td>

</tr>

<tr>

<td>B) Faster transaction processing speed</td>

</tr>

<tr>
<td>C) More secure than PoW</td>

</tr>

<tr>

<td>D) Requires fewer validators</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>120. What is the role of gas limits in Ethereum transactions?</b></td>

</tr>

<tr>

<td>A) They specify the maximum amount of Ether that can be transferred</td>

</tr>

<tr>

<td>B) They restrict the number of smart contracts that can be executed</td>

</tr>

<tr>

<td>C) They set the maximum computational work that can be performed in a transaction</td>

</tr>

<tr>

<td>D) They determine the minimum Ether required to perform a transaction</td>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>121. How does Ethereum achieve consensus in its network?</b></td>

</tr>

<tr>

<td>A) Through Proof of Work (PoW)</td>

</tr>

<tr>

<td>B) Through Proof of Stake (PoS)</td>

</tr>

<tr>

<td>C) Through Proof of Authority (PoA)</td>

</tr>

<tr>

<td>D) Through both Proof of Work and Proof of Stake</td>

</tr>

<tr>

<td>Correct answer: D</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>122. Which programming language is primarily used to write smart contracts on the Ethereum
blockchain?</b></td>

</tr>

<tr>

<td>A) JavaScript</td>

</tr>

<tr>

<td>B) Solidity</td>

</tr>

<tr>

<td>C) Python</td>

</tr>

<tr>

<td>D) Go</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>123. Which Ethereum component allows the implementation of smart contracts?</b></td>

</tr>

<tr>

<td>A) Ethereum Virtual Machine (EVM)</td>

</tr>

<tr>

<td>B) Ethereum Wallet</td>

</tr>

<tr>

<td>C) Ethereum Explorer</td>

</tr>

<tr>

<td>D) Ethereum Name Service (ENS)</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>124. What is the function of the Ethereum Name Service (ENS)?</b></td>

</tr>

<tr>

<td>A) To create tokens on the Ethereum network</td>

<tr>

<td>B) To map human-readable domain names to Ethereum addresses</td>

</tr>

<tr>

<td>C) To store smart contract data</td>

</tr>

<tr>

<td>D) To mine Ether on behalf of users</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>125. What is a 'token' in the Ethereum ecosystem?</b></td>

</tr>

<tr>

<td>A) A unit of Ether</td>

</tr>

<tr>

<td>B) A type of cryptocurrency that is created and managed by smart contracts</td>

</tr>
<tr>

<td>C) A piece of data that contains a user's private key</td>

</tr>

<tr>

<td>D) A digital wallet for storing Ether</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>126. What is an ERC-20 token?</b></td>

</tr>

<tr>

<td>A) A token used to pay for gas fees</td>

</tr>

<tr>

<td>B) A token standard for creating fungible tokens on the Ethereum blockchain</td>

</tr>

<tr>

<td>C) A token used for identity verification</td>

</tr>

<tr>
<td>D) A token used exclusively for decentralized finance (DeFi)</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>127. Which of the following is a major difference between ERC-20 tokens and ERC-721
tokens?</b></td>

</tr>

<tr>

<td>A) ERC-20 tokens are non-fungible, while ERC-721 tokens are fungible</td>

</tr>

<tr>

<td>B) ERC-20 tokens represent unique assets, while ERC-721 tokens are interchangeable</td>

</tr>

<tr>

<td>C) ERC-20 tokens are fungible, while ERC-721 tokens are non-fungible</td>

</tr>

<tr>

<td>D) ERC-20 tokens are used only for DeFi applications, while ERC-721 tokens are used for NFTs</td>

</tr>

<tr>

<td>Correct answer: C</td>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>128. What is the primary use case of an ERC-721 token?</b></td>

</tr>

<tr>

<td>A) Digital collectibles and Non-Fungible Tokens (NFTs)</td>

</tr>

<tr>

<td>B) Fungible tokens for decentralized finance (DeFi)</td>

</tr>

<tr>

<td>C) Stablecoins pegged to the US Dollar</td>

</tr>

<tr>

<td>D) Payment tokens for transaction fees</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>129. What is the Ethereum White Paper's primary purpose?</b></td>

</tr>

<tr>

<td>A) To introduce the concept of decentralized applications and smart contracts</td>

</tr>

<tr>

<td>B) To explain how Ethereum mining works</td>

</tr>

<tr>

<td>C) To provide a roadmap for Ethereum's future</td>

</tr>

<tr>

<td>D) To introduce the first decentralized cryptocurrency</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>130. What is a key advantage of Ethereum over traditional financial systems?</b></td>

</tr>

<tr>
<td>A) Faster transaction speeds</td>

</tr>

<tr>

<td>B) Complete decentralization and transparency</td>

</tr>

<tr>

<td>C) Unlimited scalability</td>

</tr>

<tr>

<td>D) Lower transaction fees for all users</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>131. What is a smart contract on the Ethereum blockchain?</b></td>

</tr>

<tr>

<td>A) A contract that requires a physical signature</td>

</tr>

<tr>

<td>B) A program that automatically executes the terms of a contract when conditions are met</td>

</tr>
<tr>

<td>C) A contract that requires human intervention to execute</td>

</tr>

<tr>

<td>D) A traditional paper-based contract stored digitally</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>132. What is the role of gas in Ethereum transactions?</b></td>

</tr>

<tr>

<td>A) Gas is used to pay for transaction fees on the network</td>

</tr>

<tr>

<td>B) Gas is used to secure transactions against fraud</td>

</tr>

<tr>

<td>C) Gas is used to track the number of tokens in a wallet</td>

</tr>

<tr>
<td>D) Gas is used to store the state of a smart contract</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>133. What does the Ethereum network use to maintain consensus?</b></td>

</tr>

<tr>

<td>A) Proof of Work</td>

</tr>

<tr>

<td>B) Proof of Stake</td>

</tr>

<tr>

<td>C) Proof of Authority</td>

</tr>

<tr>

<td>D) All of the above</td>

</tr>

<tr>

<td>Correct answer: D</td>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>134. What is the purpose of the Ethereum Virtual Machine (EVM)?</b></td>

</tr>

<tr>

<td>A) To execute smart contracts on the Ethereum network</td>

</tr>

<tr>

<td>B) To store Ethereum wallets</td>

</tr>

<tr>

<td>C) To manage transactions on the Ethereum blockchain</td>

</tr>

<tr>

<td>D) To encrypt transaction data</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>135. What is the advantage of using decentralized finance (DeFi) on Ethereum?</b></td>

</tr>

<tr>

<td>A) It allows for faster and cheaper transactions</td>

</tr>

<tr>

<td>B) It offers traditional banking services without intermediaries</td>

</tr>

<tr>

<td>C) It eliminates the need for smart contracts</td>

</tr>

<tr>

<td>D) It restricts access to financial services to a select group of people</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>136. What is the function of the 'block' in Ethereum?</b></td>

</tr>

<tr>
<td>A) To store Ether balances</td>

</tr>

<tr>

<td>B) To contain the records of Ethereum transactions</td>

</tr>

<tr>

<td>C) To verify smart contracts</td>

</tr>

<tr>

<td>D) To store the Ethereum consensus mechanism</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>137. Which of the following is true about Ethereum gas fees?</b></td>

</tr>

<tr>

<td>A) Gas fees are paid in Ether and are used to incentivize miners or validators</td>

</tr>

<tr>

<td>B) Gas fees are fixed and do not change based on network demand</td>
</tr>

<tr>

<td>C) Gas fees are used to pay for transaction validation only</td>

</tr>

<tr>

<td>D) Gas fees are paid in fiat currency</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>138. What is the purpose of an Ethereum miner?</b></td>

</tr>

<tr>

<td>A) To validate transactions and create new blocks in exchange for rewards</td>

</tr>

<tr>

<td>B) To create and deploy smart contracts</td>

</tr>

<tr>

<td>C) To secure the Ethereum wallet</td>

</tr>
<tr>

<td>D) To store transaction data</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>139. Which of the following describes a characteristic of Ethereum smart contracts?</b></td>

</tr>

<tr>

<td>A) They can only be modified by miners</td>

</tr>

<tr>

<td>B) They are executed automatically when predefined conditions are met</td>

</tr>

<tr>

<td>C) They can be used only by government entities</td>

</tr>

<tr>

<td>D) They require third-party mediation to execute</td>

</tr>

<tr>
<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>140. How can Ethereum's decentralized nature benefit businesses?</b></td>

</tr>

<tr>

<td>A) By eliminating the need for third-party intermediaries in transactions</td>

</tr>

<tr>

<td>B) By ensuring faster transaction settlement times</td>

</tr>

<tr>

<td>C) By reducing transaction costs associated with traditional financial institutions</td>

</tr>

<tr>

<td>D) All of the above</td>

</tr>

<tr>

<td>Correct answer: D</td>

</tr>

<tr>
<td></td></tr><tr><td class="questiontableheader"><br/>

<b>141. What are 'gas prices' in Ethereum?</b></td>

</tr>

<tr>

<td>A) The amount of Ether required to interact with the Ethereum network</td>

</tr>

<tr>

<td>B) The total fees required to deploy a smart contract</td>

</tr>

<tr>

<td>C) The cost of maintaining an Ethereum wallet</td>

</tr>

<tr>

<td>D) The price of Ether in the market</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>142. What is an ERC-1155 token?</b></td>

</tr>
<tr>

<td>A) A multi-token standard that allows both fungible and non-fungible tokens to coexist</td>

</tr>

<tr>

<td>B) A token used exclusively for decentralized finance applications</td>

</tr>

<tr>

<td>C) A standard for stablecoins pegged to the value of a fiat currency</td>

</tr>

<tr>

<td>D) A token standard for decentralized autonomous organizations (DAOs)</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>143. What is the main function of the 'nonce' in an Ethereum transaction?</b></td>

</tr>

<tr>

<td>A) To verify the sender's identity</td>

</tr>

<tr>
<td>B) To prevent double-spending and replay attacks</td>

</tr>

<tr>

<td>C) To encrypt the transaction data</td>

</tr>

<tr>

<td>D) To store the transaction signature</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>144. What is a Decentralized Autonomous Organization (DAO) on Ethereum?</b></td>

</tr>

<tr>

<td>A) A centralized group of people controlling Ethereum smart contracts</td>

</tr>

<tr>

<td>B) A community-led organization that operates using smart contracts on the Ethereum
blockchain</td>

</tr>

<tr>

<td>C) A business that uses Ethereum for transaction processing only</td>

<tr>

<td>D) A platform for Ethereum smart contract execution</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>145. What does 'staking' mean in the context of Ethereum 2.0?</b></td>

</tr>

<tr>

<td>A) Mining Ether to earn rewards</td>

</tr>

<tr>

<td>B) Locking up Ether in the network to participate in the Proof of Stake consensus mechanism</td>

</tr>

<tr>

<td>C) Storing Ether in a wallet</td>

</tr>

<tr>

<td>D) Trading Ether for another cryptocurrency</td>

</tr>
<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>146. What is the function of the 'blockchain explorer' in Ethereum?</b></td>

</tr>

<tr>

<td>A) To view Ethereum transaction history, blocks, and smart contracts</td>

</tr>

<tr>

<td>B) To mine Ether from the blockchain</td>

</tr>

<tr>

<td>C) To verify smart contract code</td>

</tr>

<tr>

<td>D) To create new Ethereum addresses</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>147. What is the benefit of using Ethereum over traditional banking systems?</b></td>

</tr>

<tr>

<td>A) Ethereum transactions are faster and have no fees</td>

</tr>

<tr>

<td>B) Ethereum operates globally without intermediaries and provides greater privacy</td>

</tr>

<tr>

<td>C) Ethereum has no regulatory oversight</td>

</tr>

<tr>

<td>D) Ethereum does not require an internet connection</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>148. What is the maximum number of Ethereum tokens that can exist?</b></td>
</tr>

<tr>

<td>A) 100 million</td>

</tr>

<tr>

<td>B) 21 million</td>

</tr>

<tr>

<td>C) No fixed maximum limit</td>

</tr>

<tr>

<td>D) 50 billion</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>149. What is the difference between ERC-20 and ERC-721 tokens?</b></td>

</tr>

<tr>

<td>A) ERC-20 tokens are fungible, while ERC-721 tokens are non-fungible</td>

</tr>
<tr>

<td>B) ERC-20 tokens are used for decentralized finance only, while ERC-721 tokens are used for
NFTs</td>

</tr>

<tr>

<td>C) ERC-20 tokens are primarily used in Ethereum 2.0</td>

</tr>

<tr>

<td>D) There is no difference</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>150. What does the 'gas limit' refer to in an Ethereum transaction?</b></td>

</tr>

<tr>

<td>A) The maximum amount of Ether that can be sent in one transaction</td>

</tr>

<tr>

<td>B) The maximum amount of computational work that can be done for the transaction</td>

</tr>

<tr>
<td>C) The maximum number of smart contracts that can be deployed in a block</td>

</tr>

<tr>

<td>D) The maximum number of miners required to process a transaction</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>151. What is the key innovation of Bitcoin's proof-of-work mechanism?</b></td>

</tr>

<tr>

<td>A) It ensures fast transactions with low fees</td>

</tr>

<tr>

<td>B) It allows decentralized verification of transactions</td>

</tr>

<tr>

<td>C) It eliminates the need for encryption</td>

</tr>

<tr>

<td>D) It centralizes control of the network</td>

</tr>
<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>152. What is a Bitcoin wallet?</b></td>

</tr>

<tr>

<td>A) A physical device used to store Bitcoin</td>

</tr>

<tr>

<td>B) A software program that stores a user's private and public keys</td>

</tr>

<tr>

<td>C) A service that converts Bitcoin to fiat currency</td>

</tr>

<tr>

<td>D) A network of Bitcoin miners</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>153. What does it mean when Bitcoin transactions are said to be irreversible?</b></td>

</tr>

<tr>

<td>A) Transactions can be reversed by the miner</td>

</tr>

<tr>

<td>B) Once confirmed, transactions cannot be undone or reversed</td>

</tr>

<tr>

<td>C) Transactions can be reversed by the Bitcoin foundation</td>

</tr>

<tr>

<td>D) Transactions can be undone by the sender at any time</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>154. What is the role of miners in the Bitcoin network?</b></td>

<tr>

<td>A) To create new bitcoins by mining</td>

</tr>

<tr>

<td>B) To validate and confirm transactions</td>

</tr>

<tr>

<td>C) To provide wallets for users</td>

</tr>

<tr>

<td>D) Both A and B</td>

</tr>

<tr>

<td>Correct answer: D</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>155. What is the main advantage of decentralization in Bitcoin?</b></td>

</tr>

<tr>

<td>A) Increased control by government authorities</td>

</tr>
<tr>

<td>B) No single point of failure or central authority</td>

</tr>

<tr>

<td>C) Faster transaction processing</td>

</tr>

<tr>

<td>D) Lower energy consumption</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>156. Which of the following describes the process of 'mining' in the context of Bitcoin?</b></td>

</tr>

<tr>

<td>A) The process of creating new Bitcoin wallets</td>

</tr>

<tr>

<td>B) The process of solving cryptographic puzzles to validate and add blocks to the blockchain</td>

</tr>

<tr>
<td>C) The process of transferring Bitcoin between wallets</td>

</tr>

<tr>

<td>D) The process of investing in Bitcoin-related businesses</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>157. What is a Bitcoin "blockchain"?</b></td>

</tr>

<tr>

<td>A) A list of all Bitcoin transactions, secured using cryptography</td>

</tr>

<tr>

<td>B) A type of Bitcoin wallet</td>

</tr>

<tr>

<td>C) A type of Bitcoin mining pool</td>

</tr>

<tr>

<td>D) A system that exchanges Bitcoin for fiat currency</td>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>158. What is the purpose of the Bitcoin halving event?</b></td>

</tr>

<tr>

<td>A) To increase the supply of Bitcoin in the market</td>

</tr>

<tr>

<td>B) To reduce the number of Bitcoin transactions</td>

</tr>

<tr>

<td>C) To decrease the reward for mining Bitcoin and control inflation</td>

</tr>

<tr>

<td>D) To make Bitcoin easier to mine</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>
<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>159. What does a Bitcoin "address" represent?</b></td>

</tr>

<tr>

<td>A) The physical location of the miner</td>

</tr>

<tr>

<td>B) A unique identifier used to receive Bitcoin transactions</td>

</tr>

<tr>

<td>C) A wallet password</td>

</tr>

<tr>

<td>D) A type of cryptographic key</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>160. What is the difference between Bitcoin and Bitcoin Cash?</b></td>

</tr>

<tr>

<td>A) Bitcoin Cash is more secure than Bitcoin</td>

</tr>

<tr>

<td>B) Bitcoin Cash has a larger block size, allowing for faster transactions</td>

</tr>

<tr>

<td>C) Bitcoin is used for digital cash payments, while Bitcoin Cash is used for investments</td>

</tr>

<tr>

<td>D) Bitcoin Cash is decentralized, while Bitcoin is centralized</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>161. What does the term "double spending" refer to in the Bitcoin network?</b></td>

</tr>

<tr>

<td>A) Spending the same Bitcoin twice</td>

<tr>

<td>B) Spending more Bitcoin than is available in the wallet</td>

</tr>

<tr>

<td>C) Sending Bitcoin to multiple addresses simultaneously</td>

</tr>

<tr>

<td>D) Converting Bitcoin into fiat currency</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>162. Which of the following is true about the Bitcoin ledger?</b></td>

</tr>

<tr>

<td>A) It is centrally controlled by the Bitcoin Foundation</td>

</tr>

<tr>

<td>B) It is stored in multiple copies across the network and cannot be altered</td>

</tr>
<tr>

<td>C) It is stored in a physical location in one country</td>

</tr>

<tr>

<td>D) It is not public and only accessible to miners</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>163. How does Bitcoin ensure the security of its network?</b></td>

</tr>

<tr>

<td>A) By using cryptographic hash functions and proof-of-work consensus</td>

</tr>

<tr>

<td>B) By requiring physical signatures for transactions</td>

</tr>

<tr>

<td>C) By regulating the price of Bitcoin</td>

</tr>

<tr>
<td>D) By using centralized servers</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>164. What is the role of "cryptographic hashes" in Bitcoin?</b></td>

</tr>

<tr>

<td>A) To secure transaction data and link blocks together</td>

</tr>

<tr>

<td>B) To encrypt Bitcoin wallet passwords</td>

</tr>

<tr>

<td>C) To convert fiat currency to Bitcoin</td>

</tr>

<tr>

<td>D) To validate transactions without the need for miners</td>

</tr>

<tr>

<td>Correct answer: A</td>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>165. What happens when a Bitcoin transaction is confirmed by a miner?</b></td>

</tr>

<tr>

<td>A) The transaction is added to the blockchain and cannot be changed</td>

</tr>

<tr>

<td>B) The transaction is removed from the network</td>

</tr>

<tr>

<td>C) The transaction is refunded to the sender</td>

</tr>

<tr>

<td>D) The transaction is stored in a private ledger</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>166. What is a "private key" in Bitcoin?</b></td>

</tr>

<tr>

<td>A) A public address used to receive Bitcoin</td>

</tr>

<tr>

<td>B) A secret number used to sign Bitcoin transactions and prove ownership</td>

</tr>

<tr>

<td>C) A transaction ID that is unique to each transaction</td>

</tr>

<tr>

<td>D) A type of Bitcoin wallet</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>167. What does the Bitcoin protocol's "difficulty adjustment" mechanism do?</b></td>

</tr>

<tr>
<td>A) It ensures that blocks are mined at a constant rate by adjusting mining difficulty</td>

</tr>

<tr>

<td>B) It controls the reward that miners receive</td>

</tr>

<tr>

<td>C) It increases the supply of Bitcoin to prevent inflation</td>

</tr>

<tr>

<td>D) It changes the proof-of-work algorithm</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>168. How often does the Bitcoin halving event occur?</b></td>

</tr>

<tr>

<td>A) Every year</td>

</tr>

<tr>

<td>B) Every 10,000 blocks</td>

<tr>

<td>C) Every 210,000 blocks</td>

</tr>

<tr>

<td>D) Every 100,000 blocks</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>169. What is a "block reward" in Bitcoin?</b></td>

</tr>

<tr>

<td>A) The fee paid to miners for adding a block to the blockchain</td>

</tr>

<tr>

<td>B) The reward given to miners for validating transactions</td>

</tr>

<tr>

<td>C) The amount of Bitcoin created with each new block</td>

</tr>
<tr>

<td>D) Both A and C</td>

</tr>

<tr>

<td>Correct answer: D</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>170. What is the purpose of the Bitcoin "genesis block"?</b></td>

</tr>

<tr>

<td>A) To mark the beginning of the Bitcoin blockchain</td>

</tr>

<tr>

<td>B) To store all of the transaction data</td>

</tr>

<tr>

<td>C) To reward the first miner in the network</td>

</tr>

<tr>

<td>D) To create the initial supply of Bitcoin</td>

</tr>

<tr>
<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>171. What is the Bitcoin "difficulty" in mining?</b></td>

</tr>

<tr>

<td>A) The total number of transactions per block</td>

</tr>

<tr>

<td>B) The measure of how difficult it is to find a valid hash for a block</td>

</tr>

<tr>

<td>C) The reward miners receive for adding a block</td>

</tr>

<tr>

<td>D) The total number of blocks mined</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>172. What is the significance of Bitcoin’s proof-of-work (PoW) consensus algorithm?</b></td>

</tr>

<tr>

<td>A) It provides a way to manage Bitcoin's monetary policy</td>

</tr>

<tr>

<td>B) It allows decentralized decision-making in the network</td>

</tr>

<tr>

<td>C) It helps secure the network by making it difficult to alter transaction history</td>

</tr>

<tr>

<td>D) It lowers transaction fees by increasing block size</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>173. What does it mean when Bitcoin transactions are "peer-to-peer"?</b></td>

</tr>

<tr>
<td>A) Transactions are made directly between parties without a central authority</td>

</tr>

<tr>

<td>B) Transactions involve multiple intermediaries</td>

</tr>

<tr>

<td>C) Transactions are stored in a central database</td>

</tr>

<tr>

<td>D) Transactions are automatically approved by government institutions</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>174. Which cryptographic algorithm is used by Bitcoin for transaction security?</b></td>

</tr>

<tr>

<td>A) RSA</td>

</tr>

<tr>

<td>B) SHA-256</td>
</tr>

<tr>

<td>C) AES-256</td>

</tr>

<tr>

<td>D) DES</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>175. How is the supply of Bitcoin limited?</b></td>

</tr>

<tr>

<td>A) Bitcoin's source code has a hard cap of 21 million coins</td>

</tr>

<tr>

<td>B) The Bitcoin Foundation regulates the supply</td>

</tr>

<tr>

<td>C) Governments control the issuance of Bitcoin</td>

</tr>
<tr>

<td>D) Bitcoin can be mined without limits</td>

</tr>

<tr>

<td>Correct answer: A</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>176. How does Bitcoin achieve immutability?</b></td>

</tr>

<tr>

<td>A) By using a centralized database</td>

</tr>

<tr>

<td>B) Through the cryptographic verification of each block and its interlinking with the previous
one</td>

</tr>

<tr>

<td>C) By limiting the number of transactions per block</td>

</tr>

<tr>

<td>D) By increasing the size of the blockchain</td>

</tr>

<tr>
<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>177. What is the purpose of Bitcoin’s transaction fees?</b></td>

</tr>

<tr>

<td>A) To penalize users for making transactions</td>

</tr>

<tr>

<td>B) To pay miners for including transactions in the blockchain</td>

</tr>

<tr>

<td>C) To regulate the flow of Bitcoin</td>

</tr>

<tr>

<td>D) To fund Bitcoin development projects</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>
<td></td></tr><tr><td class="questiontableheader"><br/>

<b>178. What does "soft fork" mean in the context of Bitcoin?</b></td>

</tr>

<tr>

<td>A) A change to the protocol that is incompatible with older versions</td>

</tr>

<tr>

<td>B) A temporary fork in the blockchain to prevent double-spending</td>

</tr>

<tr>

<td>C) A change that is backward-compatible with older versions of the protocol</td>

</tr>

<tr>

<td>D) A hard division of the Bitcoin network into two competing chains</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>179. What is "mining difficulty" in Bitcoin?</b></td>

</tr>
<tr>

<td>A) The number of blocks a miner must find before receiving a reward</td>

</tr>

<tr>

<td>B) The degree of computational effort required to find a valid block hash</td>

</tr>

<tr>

<td>C) The reward a miner receives for validating a block</td>

</tr>

<tr>

<td>D) The number of transactions in a block</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>180. How does Bitcoin prevent Sybil attacks?</b></td>

</tr>

<tr>

<td>A) By using proof-of-stake consensus</td>

</tr>

<tr>
<td>B) By requiring miners to solve a difficult cryptographic puzzle</td>

</tr>

<tr>

<td>C) By requiring users to verify their identity</td>

</tr>

<tr>

<td>D) By limiting the number of transactions per day</td>

</tr>

<tr>

<td>Correct answer: B</td>

</tr>

<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>181. What is a "51% attack" in Bitcoin?</b></td>

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<td>A) When more than 50% of Bitcoin transactions are invalidated</td>

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<td>B) When an attacker controls more than 50% of the network's mining power and can potentially
rewrite the blockchain</td>

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<td>C) When an attacker steals more than 51% of Bitcoin's total supply</td>
</tr>

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<td>D) When Bitcoin's protocol changes by 51%</td>

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<td>Correct answer: B</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>182. What is the maximum number of Bitcoins that can ever exist?</b></td>

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<td>A) 10 million</td>

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<td>B) 21 million</td>

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<td>C) 50 million</td>

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<td>D) 100 million</td>

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<td>Correct answer: B</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>183. What is the main reason Bitcoin uses proof-of-work?</b></td>

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<td>A) To provide rewards to miners</td>

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<td>B) To make it difficult for an attacker to alter the blockchain</td>

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<td>C) To facilitate faster transaction times</td>

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<td>D) To reduce the supply of Bitcoin</td>

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<td>Correct answer: B</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>184. What does it mean when Bitcoin is described as "trustless"?</b></td>

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<td>A) Bitcoin transactions do not require trust in a central authority</td>

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<td>B) Bitcoin transactions are anonymous and untraceable</td>

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<td>C) Bitcoin is not backed by any government</td>

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<td>D) Bitcoin does not rely on encryption</td>

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<td>Correct answer: A</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>185. How do Bitcoin nodes maintain consensus?</b></td>

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<td>A) By relying on a single central server for transaction verification</td>

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<td>B) By voting on each transaction</td>

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<td>C) By following the longest valid chain rule and ensuring they are in sync with the majority of the
network</td>

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<td>D) By limiting the number of transactions allowed per minute</td>

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<td>Correct answer: C</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>186. What is the purpose of the Bitcoin block size limit?</b></td>

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<td>A) To increase the transaction speed</td>

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<td>B) To limit the number of transactions in a block and prevent abuse of the network</td>

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<td>C) To control the total supply of Bitcoin</td>

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<td>D) To increase the total number of Bitcoins available</td>

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<td>Correct answer: B</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>187. What does "double-spending" refer to in Bitcoin?</b></td>

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<td>A) Spending the same Bitcoin twice by using two different addresses</td>

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<td>B) The ability to send multiple transactions in the same block</td>

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<td>C) Sending a Bitcoin transaction to two different miners</td>

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<td>D) The process of converting Bitcoin into fiat currency</td>

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<td>Correct answer: A</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>188. Which of the following is a feature of the Bitcoin blockchain?</b></td>

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<td>A) Decentralization</td>

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<td>B) Centralized control</td>

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<td>C) Full anonymity for users</td>

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<td>D) Unlimited transaction size</td>

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<tr>

<td>Correct answer: A</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>189. How are Bitcoin transactions verified?</b></td>

</tr>

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<td>A) Through a consensus among Bitcoin miners using proof-of-work</td>

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<td>B) By the central Bitcoin authority</td>

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<td>C) By relying on trusted third parties</td>

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<td>D) By verifying users' identities through a database</td>

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<td>Correct answer: A</td>

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<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>190. What does "timestamping" mean in the context of Bitcoin transactions?</b></td>

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<td>A) The process of confirming when a Bitcoin transaction was executed</td>

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<td>B) The encryption of Bitcoin wallets</td>

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<td>C) The process of recording the public address of the sender</td>

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<td>D) The validation of each Bitcoin transaction through a time-based token</td>

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<td>Correct answer: A</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>191. Which term refers to a Bitcoin user's private key?</b></td>

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<td>A) Public address</td>

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<td>B) Wallet</td>

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<td>C) Secret key</td>

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<td>D) Digital signature</td>

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<td>Correct answer: C</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>192. What is a "hard fork" in Bitcoin?</b></td>

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<td>A) A temporary split in the blockchain that does not affect consensus</td>

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<tr>

<td>B) A permanent divergence of the blockchain that leads to two separate versions</td>

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<td>C) A change in Bitcoin's difficulty adjustment algorithm</td>

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<td>D) A method of fixing double-spending issues</td>

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<td>Correct answer: B</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>193. What is the role of miners in the Bitcoin network?</b></td>

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<td>A) To approve transactions without verifying them</td>

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<td>B) To generate new Bitcoins through proof-of-work</td>

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<td>C) To control the issuance of new Bitcoin blocks</td>

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<td>D) To create Bitcoin wallets for users</td>

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<td>Correct answer: B</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>194. What is the main advantage of Bitcoin's decentralized nature?</b></td>

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<td>A) It allows for greater control over transaction validation</td>

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<td>B) It eliminates the need for intermediaries like banks</td>

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<td>C) It increases the centralization of Bitcoin's operations</td>

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<td>D) It ensures that Bitcoin is completely anonymous</td>

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<td>Correct answer: B</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>195. What is a Bitcoin "address"?</b></td>

</tr>

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<td>A) A unique string of characters used to send or receive Bitcoin</td>

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<td>B) A private key used to access the wallet</td>

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<td>C) A public key associated with a user's identity</td>

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<td>D) A transaction ID that confirms payment</td>

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<td>Correct answer: A</td>

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<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>

<b>196. What is the primary purpose of a Bitcoin wallet?</b></td>

</tr>

<tr>

<td>A) To store Bitcoin and manage the private keys used for transactions</td>

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<td>B) To act as an exchange between fiat and Bitcoin</td>

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<tr>

<td>C) To increase the size of Bitcoin blocks</td>

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<tr>

<td>D) To create new Bitcoin transactions</td>

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<td>Correct answer: A</td>

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<tr>

<td></td></tr><tr><td class="questiontableheader"><br/>
<b>197. What is Bitcoin's primary security mechanism against fraudulent transactions?</b></td>

</tr>

<tr>

<td>A) A public ledger of all transactions called the blockchain</td>

</tr>

<tr>

<td>B) Biometric authentication of users</td>

</tr>

<tr>

<td>C) The use of decentralized exchanges</td>

</tr>

<tr>

<td>D) Centralized control by the Bitcoin Foundation</td>

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<td>Correct answer: A</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>198. What is the function of the "nonce" in the Bitcoin mining process?</b></td>

</tr>

<tr>

<td>A) It ensures that transactions are valid and verified</td>

<tr>

<td>B) It is the random value that miners change to find a valid block hash</td>

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<td>C) It is used to calculate transaction fees</td>

</tr>

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<td>D) It stores the private keys of Bitcoin users</td>

</tr>

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<td>Correct answer: B</td>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>199. Which of the following is true about Bitcoin transaction fees?</b></td>

</tr>

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<td>A) They are fixed by the Bitcoin protocol</td>

</tr>

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<td>B) They are paid directly to Bitcoin developers</td>

</tr>
<tr>

<td>C) They are paid to miners who include the transaction in a block</td>

</tr>

<tr>

<td>D) They are used to increase the block size limit</td>

</tr>

<tr>

<td>Correct answer: C</td>

</tr>

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<td></td></tr><tr><td class="questiontableheader"><br/>

<b>200. What happens when Bitcoin's block reward halving occurs?</b></td>

</tr>

<tr>

<td>A) The total number of Bitcoins available increases</td>

</tr>

<tr>

<td>B) The reward that miners receive for mining a block is reduced by half</td>

</tr>

<tr>

<td>C) Bitcoin's transaction fees increase</td>

</tr>

<tr>
<td>D) The difficulty of mining decreases</td>

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<tr>

<td>Correct answer: B</td>

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