Biology

Q1: What is the function of mitochondria in the cell?

A: It produces energy through cellular respiration.

Q2: What process moves water across a cell membrane?

A: Osmosis.

Q3: What are the two types of cell division?

A: Mitosis and meiosis.

Q4: What molecule carries genetic information?

A: DNA.

Q5: What is photosynthesis?

A: A process where plants use sunlight to make food (glucose).

Q6: What is natural selection?

A: The process where organisms better adapted to their environment survive and reproduce.

⚗️Chemistry
Q1: What are the three main states of matter?
A: Solid, liquid, gas.

Q2: What is the smallest unit of an element?

A: An atom.

Q3: What is the charge of a proton?

A: Positive.

Q4: What kind of bond involves the sharing of electrons?

A: Covalent bond.

Q5: What is the formula to calculate density?

A: Density = Mass / Volume.

Q6: What is the pH range of an acid?

A: Less than 7.

⚙️Physics
Q1: What is the first law of motion by Newton?
A: An object will remain at rest or in motion unless acted on by a force.

Q2: What unit is used to measure force?

A: Newton (N).

Q3: What is the formula for speed?

A: Speed = Distance / Time.
Q4: What is kinetic energy?
A: Energy of a moving object.

Q5: What type of wave is sound?

A: Mechanical wave.

Q6: What causes refraction of light?

A: Change in speed as it passes through different materials.

🌍 Earth & Environmental Science

Q1: What causes earthquakes?
A: Movement of tectonic plates.

Q2: What layer of Earth do we live on?

A: The crust.

Q3: What is the greenhouse effect?

A: Warming of Earth’s surface due to trapped heat.

Q4: Name one renewable energy source.

A: Solar energy.

Q5: What is the process of breaking down waste by living organisms?

A: Decomposition.

Q6: What sphere includes all water on Earth?

A: Hydrosphere.

🌌 Space Science
Q1: What is the center of our solar system?
A: The Sun.

Q2: What is a galaxy?

A: A large group of stars, gas, and dust held together by gravity.

Q3: What is the name of our galaxy?

A: The Milky Way.

Q4: What is a black hole?

A: A region in space with strong gravity that nothing can escape from.

Q5: What tool do astronomers use to observe space?

A: A telescope.

Q6: What is space medicine?

A: The study of how space affects human health.
Biology – Part 2
1. The basic unit of structure and function in living organisms.
→ Cell
2. The part of the cell that controls what enters and leaves.
→ Cell membrane
3. The process where cells use oxygen to break down food and release energy.
→ Cellular respiration
4. The organelle responsible for making proteins.
→ Ribosome
5. The passing of traits from parents to offspring.
→ Heredity
6. A diagram used to show possible genetic combinations.
→ Punnett square
7. A grouping of organisms that can interbreed and produce fertile offspring.
→ Species

⚗️Chemistry – Part 2
1. A negatively charged particle found in the outer part of an atom.
→ Electron
2. The positively charged center of an atom.
→ Nucleus (atomic nucleus)
3. A pure substance made of only one kind of atom.
→ Element
4. A substance made from two or more elements chemically combined.
→ Compound
5. The number of particles in one mole of a substance (6.022 × 10²³).
→ Avogadro’s Number
6. The total mass of reactants equals the total mass of products.
→ Law of Conservation of Mass
7. The simplest ratio of atoms in an ionic compound.
→ Empirical formula

⚙️Physics – Part 2
1. The resistance of any physical object to a change in its motion.
→ Inertia
2. A push or pull on an object.
→ Force
3. A quantity that has both magnitude and direction.
→ Vector
4. Stored energy due to position or condition.
→ Potential energy
5. The amount of work done per unit of time.
→ Power
6. The measure of how much matter an object contains.
→ Mass
7. The rate of change of velocity.
→ Acceleration
🌍 Earth & Environmental Science – Part 2
1. The outermost layer of the Earth.
→ Crust
2. Molten rock beneath the Earth's surface.
→ Magma
3. A natural process that moves weathered rock and soil from one place to another.
→ Erosion
4. The warming of the Earth's surface due to trapped heat by gases.
→ Greenhouse effect
5. The wise use and protection of natural resources.
→ Conservation
6. A material formed from the remains of plants and animals over millions of years.
→ Fossil fuel
7. The number of individuals of a species in a given area.
→ Population density

🌌 Space Science – Part 2

1. The path an object takes around another object in space.
→ Orbit
2. An object that produces its own light and is made mostly of hydrogen and helium.
→ Star
3. A small rocky body that orbits the sun, mostly found in the asteroid belt.
→ Asteroid
4. Chunks of ice and dust with tails that orbit the sun.
→ Comet
5. A space object that enters Earth's atmosphere and burns up.
→ Meteor
6. The force that keeps planets in orbit around the sun.
→ Gravity
7. A spacecraft with no people on board, used to collect data.
→ Space probe

Biology – Part 2
1. The basic unit of structure and function in living organisms.
→ Cell
2. The part of the cell that controls what enters and leaves.
→ Cell membrane
3. The process where cells use oxygen to break down food and release energy.
→ Cellular respiration
4. The organelle responsible for making proteins.
→ Ribosome
5. The passing of traits from parents to offspring.
→ Heredity
6. A diagram used to show possible genetic combinations.
→ Punnett square
7. A grouping of organisms that can interbreed and produce fertile offspring.
→ Species
⚗️Chemistry – Part 2
1. A negatively charged particle found in the outer part of an atom.
→ Electron
2. The positively charged center of an atom.
→ Nucleus (atomic nucleus)
3. A pure substance made of only one kind of atom.
→ Element
4. A substance made from two or more elements chemically combined.
→ Compound
5. The number of particles in one mole of a substance (6.022 × 10²³).
→ Avogadro’s Number
6. The total mass of reactants equals the total mass of products.
→ Law of Conservation of Mass
7. The simplest ratio of atoms in an ionic compound.
→ Empirical formula

⚙️Physics – Part 2
1. The resistance of any physical object to a change in its motion.
→ Inertia
2. A push or pull on an object.
→ Force
3. A quantity that has both magnitude and direction.
→ Vector
4. Stored energy due to position or condition.
→ Potential energy
5. The amount of work done per unit of time.
→ Power
6. The measure of how much matter an object contains.
→ Mass
7. The rate of change of velocity.
→ Acceleration

🌍 Earth & Environmental Science – Part 2

1. The outermost layer of the Earth.
→ Crust
2. Molten rock beneath the Earth's surface.
→ Magma
3. A natural process that moves weathered rock and soil from one place to another.
→ Erosion
4. The warming of the Earth's surface due to trapped heat by gases.
→ Greenhouse effect
5. The wise use and protection of natural resources.
→ Conservation
6. A material formed from the remains of plants and animals over millions of years.
→ Fossil fuel
 7. The number of individuals of a species in a given area.
→ Population density

🌌 Space Science – Part 2

1. The path an object takes around another object in space.
→ Orbit
2. An object that produces its own light and is made mostly of hydrogen and helium.
→ Star
3. A small rocky body that orbits the sun, mostly found in the asteroid belt.
→ Asteroid
4. Chunks of ice and dust with tails that orbit the sun.
→ Comet
5. A space object that enters Earth's atmosphere and burns up.
→ Meteor
6. The force that keeps planets in orbit around the sun.
→ Gravity
7. A spacecraft with no people on board, used to collect data.
→ Space probe

Biology

Define first:
“The process where cells divide to create two different gametes, each with half the original chromosome
number.”
→ Answer: Meiosis

Chemistry

Define first:
“A bond in which electrons are fully transferred, creating charged particles.”
→ Answer: Ionic bond

Physics

Define first:
“The rate at which work is done or energy is transferred.”
→ Answer: Power (P = work/time)

Earth Science

Define first:
“The supercontinent that existed before continental drift separated the continents.”
→ Answer: Pangaea

Space Science

Define first:
“The apparent shift in position of a nearby star when observed from different points in Earth's orbit.”
→ Answer: Stellar parallax
📝 Practice Problem (Multi-step)
Chemistry / Stoichiometry-style
“If 2 mol H₂ reacts with 1 mol O₂ to produce water, how many grams of H₂O can form?”

 2 mol H₂ + 1 mol O₂ → 2 mol H₂O

 Molar mass H₂O ≈ 18 g/mol
 Answer: 2 moles × 18 g/mol = 36 g H₂O

Biology
Q1: What is an organelle? Give two examples.
A: An organelle is a specialized structure inside a cell that performs specific functions. Examples:
mitochondria, chloroplasts.

Q2: What is the name of the cell division that produces gametes with half the chromosome number?
A: Meiosis.

Q3: How does natural selection lead to evolution?

A: Organisms with favorable traits survive and reproduce more, passing those traits on, changing the
population over time.

Q4: What is the function of mitochondria?

A: To produce energy (ATP) through cellular respiration.

Q5: What is the difference between mitosis and meiosis?

A: Mitosis produces two identical cells for growth; meiosis produces four genetically different gametes for
reproduction.

Q6: What do we call the interaction of organisms with their environment?

A: Ecology.

Q7: What is taxonomy?

A: The classification and naming of organisms based on shared characteristics.

Chemistry
Q8: What is matter? Give an example.
A: Matter is anything that has mass and occupies space. Example: water.

Q9: State Boyle’s Law.

A: The volume of a gas decreases as pressure increases, at constant temperature.

Q10: What is an ionic bond?

A: A bond formed by the transfer of electrons between atoms, creating charged ions.

Q11: How do covalent and ionic bonds differ?

A: Covalent bonds share electrons; ionic bonds transfer electrons.

Q12: Calculate the mass of water formed from 4 moles of hydrogen gas reacting with oxygen. (2H₂ + O₂ →
2H₂O, molar mass H₂O = 18 g/mol)
A: 4 moles H₂ produce 4 moles H₂O → mass = 4 × 18 = 72 grams.
Q13: What is chemical equilibrium?
A: When forward and reverse reaction rates are equal, so concentrations stay constant.

Q14: What is electrolysis?

A: Using electric current to drive a non-spontaneous chemical reaction, like splitting water into hydrogen and
oxygen.

Physics
Q15: What is a vector? Give an example.
A: A quantity with magnitude and direction, e.g., velocity.

Q16: State Newton’s First Law.

A: Objects stay at rest or in constant motion unless acted on by an external force.

Q17: Calculate force if mass = 10 kg and acceleration = 5 m/s².

A: Force = mass × acceleration = 10 × 5 = 50 N.

Q18: Define kinetic energy and give its formula.

A: Energy of motion; KE = ½ mv².

Q19: What is conservation of momentum?

A: Total momentum in a system remains constant without external forces.

Q20: What is refraction?

A: Bending of light when passing between different media.

Q21: What is the unit of electric current?

A: Ampere (A).

Q22: Name two renewable energy sources and why they are sustainable.
A: Solar and wind energy; sustainable because they are abundant and won't run out.

Earth & Environmental Science

Q23: What is plate tectonics?
A: Movement of Earth’s crustal plates causing earthquakes, volcanoes, etc.

Q24: Name two natural hazards and how humans can prepare for them.
A: Earthquakes (build resistant structures), floods (evacuation plans).

Q25: What is the difference between weather and climate?

A: Weather is short-term atmospheric conditions; climate is long-term average.

Q26: Define sustainability.

A: Using resources so they last for future generations.

Q27: What is the biosphere?

A: All living organisms on Earth and their environments.
Space Science
Q28: What event marks the beginning of the universe?
A: The Big Bang.

Q29: What is a black hole?

A: A space region with gravity so strong that nothing can escape.

Q30: What is parallax and how is it used?

A: Apparent shift of a star’s position used to measure distances.

Q31: Name the two main bodies in the Earth-Moon system.

A: Earth and Moon.

Q32: What is space medicine?

A: Study of human health in space conditions.

Biology (continued)
Q33: What is DNA and why is it important?
A: DNA is deoxyribonucleic acid, the molecule that carries genetic information for building proteins and
traits.

Q34: What is mutation?

A: A change in the DNA sequence that can cause variation or disease.

Q35: Explain the role of protein synthesis.

A: It’s the process where cells use DNA instructions to make proteins, involving transcription and translation.

Q36: What is photosynthesis?

A: Process by which plants convert sunlight, carbon dioxide, and water into glucose and oxygen.

Q37: What is a population in biology?

A: A group of organisms of the same species living in an area.

Chemistry (continued)
Q38: Define stoichiometry.
A: The calculation of reactants and products in chemical reactions.

Q39: What are gas laws? Name one.

A: Laws that describe how gases behave; example: Charles’s Law (volume proportional to temperature at
constant pressure).

Q40: What is chemical kinetics?

A: Study of reaction rates and factors affecting them.

Q41: Define acids and bases according to the pH scale.

A: Acids have pH < 7, bases have pH > 7, neutral substances have pH = 7.

Q42: What is an organic compound? Give an example.

A: Compounds mainly made of carbon and hydrogen; example: methane (CH₄).
Physics (continued)
Q43: What is projectile motion?
A: The curved path an object follows when thrown near Earth’s surface.

Q44: What is the formula for work done?

A: Work = Force × Distance × cos(θ)

Q45: Define power in physics.

A: Rate at which work is done, measured in watts (W).

Q46: What causes mechanical waves?

A: Vibrations in a medium, such as air or water.

Q47: What is Bernoulli’s principle?

A: Faster fluid flow results in lower pressure.

Earth & Environmental Science (continued)

Q48: What are minerals?
A: Naturally occurring solid substances with definite chemical composition.

Q49: What is soil erosion and how can it be prevented?

A: Removal of topsoil by wind or water; prevented by planting vegetation or terracing.

Q50: Describe the water cycle.

A: Continuous movement of water through evaporation, condensation, precipitation, and collection.

Space Science (continued)

Q51: What are galaxies?
A: Massive systems of stars, dust, gas, and dark matter bound by gravity.

Q52: What is a solar system?

A: A star and all objects orbiting it, including planets and moons.

Q53: What is the Big Bang Theory?

A: Scientific explanation for the origin of the universe from a hot, dense state.

Q54: How do astronauts prepare for space medicine challenges?

A: By undergoing physical training and medical studies to counteract effects of microgravity and radiation.

Q55: What is a comet?

A: A small icy body that orbits the sun, often with a visible tail when near the sun.

Biology (more)
Q56: What is cell respiration?
A: The process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water.

Q57: Define population genetics.

A: The study of genetic variation within populations and how gene frequencies change over time.

Q58: What is inheritance?

A: The passing of traits from parents to offspring through genes.

Q59: What is a mutation’s effect on inheritance?

A: Mutations can introduce new traits that may be passed to offspring if they occur in reproductive cells.

Q60: What is an ecosystem?

A: A community of living organisms interacting with their physical environment.

Chemistry (more)
Q61: What is thermochemistry?
A: The study of heat changes during chemical reactions.

Q62: Define chemical thermodynamics.

A: The study of energy changes and energy flow in chemical processes.

Q63: What is a catalyst?

A: A substance that speeds up a chemical reaction without being consumed.

Q64: What are intermolecular forces?

A: Weak forces of attraction between molecules, e.g., hydrogen bonds.

Q65: What is an electrolyte?

A: A substance that produces ions and conducts electricity in solution.

Physics (more)
Q66: What is rotational dynamics?
A: Study of forces and torques causing rotation.

Q67: Define impulse.

A: Change in momentum resulting from a force applied over time.

Q68: What is the center of mass?

A: The point where the mass of an object is concentrated.

Q69: What is static electricity?

A: Accumulation of electric charge on a surface.

Q70: Describe the photoelectric effect.

A: Emission of electrons from a material when light shines on it.
Earth & Environmental Science (more)
Q71: What is climate change?
A: Long-term alteration of temperature and weather patterns, mainly due to human activity.

Q72: Define renewable resources.

A: Natural resources that can be replenished naturally over time.

Q73: What is soil pollution?

A: Contamination of soil by harmful substances.

Q74: What is deforestation?

A: Removal of forests, often causing habitat loss and climate effects.

Q75: How does urbanization affect the environment?

A: It increases pollution, reduces green areas, and changes natural water flow.

Space Science (more)

Q76: What is a nebula?
A: A cloud of gas and dust in space, often a star-forming region.

Q77: What is a star?

A: A massive ball of hot gas producing energy by nuclear fusion.

Q78: What is cosmic radiation?

A: High-energy particles from space that can affect astronauts and electronics.

Q79: What is the significance of the Hubble Space Telescope?

A: It provides detailed images of space beyond Earth’s atmosphere, helping in astronomical research.

Q80: What is zero gravity?

A: Condition in space where objects appear weightless due to free fall.

Biology — Deeper Concepts

Q106: Explain the structure and function of the cell membrane.
A: The cell membrane is a semi-permeable layer made of a lipid bilayer with proteins. It controls what enters
and exits the cell, maintaining homeostasis.

Q107: Describe the process of protein synthesis.

A: Protein synthesis has two main stages:

 Transcription: DNA is copied into messenger RNA (mRNA) in the nucleus.

 Translation: mRNA is read by ribosomes in the cytoplasm to assemble amino acids into proteins.

Q108: How do mutations affect organisms?

A: Mutations can alter DNA sequences, potentially changing protein structure and function. Some mutations
are harmful, some neutral, and some beneficial, driving evolution.

Q109: What is the role of enzymes in cellular reactions?

A: Enzymes act as biological catalysts, speeding up chemical reactions without being consumed.
Q110: Explain how photosynthesis and cellular respiration are complementary processes.
A: Photosynthesis converts carbon dioxide and water into glucose and oxygen using sunlight, while cellular
respiration breaks down glucose and oxygen to release energy, carbon dioxide, and water.

Chemistry — Deeper Concepts

Q111: Explain the difference between ionic and covalent bonds with examples.
A:

 Ionic bonds form when electrons transfer from metal to non-metal atoms (e.g., NaCl).
 Covalent bonds form when atoms share electrons (e.g., H₂O).

Q112: What factors affect reaction rates?

A: Temperature, concentration, surface area, and catalysts can increase reaction rates.

Q113: Describe the concept of molarity in solutions.

A: Molarity (M) is the number of moles of solute per liter of solution, indicating concentration.

Q114: What is the difference between an endothermic and exothermic reaction?

A: Endothermic reactions absorb heat (e.g., photosynthesis); exothermic reactions release heat (e.g.,
combustion).

Q115: Explain the role of acids and bases in neutralization reactions.

A: Acids release H⁺ ions, bases release OH⁻ ions; when mixed, they react to form water and a salt,
neutralizing each other.

Physics — Deeper Concepts

Q116: Derive the equation of motion for constant acceleration.
A: Using initial velocity uuu, acceleration aaa, time ttt, and displacement sss:
s=ut+12at2s = ut + \frac{1}{2}at^2s=ut+21at2

Q117: Explain the concept of conservation of energy with examples.

A: Energy cannot be created or destroyed, only transformed; e.g., potential energy converting to kinetic
energy in a falling object.

Q118: What is the difference between elastic and inelastic collisions?

A: Elastic collisions conserve both kinetic energy and momentum; inelastic collisions conserve momentum
but kinetic energy is lost as heat or deformation.

Q119: Explain how lenses form images.

A: Convex lenses converge light rays to a focal point forming real or virtual images depending on object
distance.

Q120: What is the Doppler effect?

A: The change in frequency or wavelength of a wave relative to an observer moving relative to the source
(e.g., ambulance siren pitch changes).
Earth & Environmental Science — Deeper Concepts
Q121: Explain the rock cycle.
A: The continuous process of rock formation: igneous rocks form from cooling magma, sedimentary rocks
form from sediment compaction, and metamorphic rocks form from heat and pressure changes.

Q122: Describe how plate tectonics causes earthquakes and volcanoes.

A: Movement and collision of tectonic plates cause stress build-up, leading to earthquakes; subduction zones
allow magma to rise and form volcanoes.

Q123: What causes global warming?

A: Increased greenhouse gases trap more heat in the atmosphere, raising Earth’s average temperature.

Q124: How do human activities affect biodiversity?

A: Pollution, deforestation, and habitat destruction reduce species diversity and threaten ecosystems.

Q125: What is the importance of wetlands?

A: Wetlands filter pollutants, provide habitat for species, and help control flooding.

Space Science — Deeper Concepts

Q126: Explain the life cycle of a star.
A: Stars form from nebulae, then main sequence stars fuse hydrogen, later becoming red giants or supernovae,
ending as white dwarfs, neutron stars, or black holes depending on mass.

Q127: How do astronomers measure distances in space?

A: Using parallax for nearby stars, standard candles like Cepheid variables for distant stars, and redshift for
galaxies.

Q128: Describe the concept of dark matter and dark energy.

A: Dark matter is invisible matter that exerts gravitational pull; dark energy causes the accelerated expansion
of the universe.

Q129: What is the significance of the cosmic microwave background radiation?

A: It is the remnant thermal radiation from the Big Bang, providing evidence of the universe’s origin.

Q130: Explain how space missions study the solar system.

A: Space probes and telescopes collect data on planets, moons, and asteroids to understand their composition,
atmosphere, and history.

Biology — Advanced Concepts

Q131: Describe the differences between prokaryotic and eukaryotic cells.
A: Prokaryotic cells lack a nucleus and membrane-bound organelles (e.g., bacteria), while eukaryotic cells
have a nucleus and organelles (e.g., plant and animal cells).

Q132: What is the role of ribosomes in a cell?

A: Ribosomes are the sites where proteins are synthesized by translating mRNA.

Q133: Explain the role of chlorophyll in photosynthesis.

A: Chlorophyll absorbs light energy, mainly blue and red wavelengths, to power the photosynthesis reaction.
Q134: How does genetic recombination occur during meiosis?
A: Homologous chromosomes exchange segments during crossing over, creating genetic variation.

Q135: What is the importance of biodiversity to ecosystems?

A: Biodiversity ensures ecosystem stability, resilience to changes, and provides resources for humans.

Chemistry — Advanced Concepts

Q136: Explain the periodic trends in atomic radius across a period and down a group.
A: Atomic radius decreases across a period due to increasing nuclear charge; it increases down a group due to
added electron shells.

Q137: Describe how to determine empirical and molecular formulas from experimental data.
A: Empirical formula is the simplest whole-number ratio of atoms; molecular formula is a multiple of the
empirical formula based on molar mass.

Q138: What is Le Chatelier’s Principle? Give an example.

A: If a system at equilibrium is disturbed, it shifts to counteract the change; e.g., increasing pressure shifts
equilibrium toward fewer gas molecules.

Q139: What is the difference between a strong and weak acid?

A: Strong acids completely ionize in solution; weak acids partially ionize.

Q140: Explain the concept of oxidation and reduction (redox reactions).

A: Oxidation is loss of electrons; reduction is gain of electrons.

Physics — Advanced Concepts

Q141: Explain the concept of torque and its formula.
A: Torque causes rotational motion; τ=r×F×sin⁡(θ)\tau = r \times F \times \sin(\theta)τ=r×F×sin(θ), where rrr is
lever arm distance.

Q142: Derive the relation between kinetic energy and work done.
A: Work done on an object changes its kinetic energy (Work-Energy Theorem).

Q143: What is the difference between static and kinetic friction?

A: Static friction prevents motion up to a threshold; kinetic friction acts when objects slide past each other.

Q144: Explain the principle of conservation of angular momentum.

A: Total angular momentum remains constant if no external torque acts on the system.

Q145: What are standing waves? Give an example.

A: Waves that remain in fixed positions due to interference; e.g., vibrations on a guitar string.

Earth & Environmental Science — Advanced Concepts

Q146: Explain the greenhouse effect and its natural importance.
A: Greenhouse gases trap infrared radiation, keeping Earth warm enough to support life.
Q147: What are the layers of the Earth’s atmosphere and their characteristics?
A: Troposphere (weather), stratosphere (ozone layer), mesosphere (meteors burn), thermosphere (auroras),
exosphere (outer space).

Q148: Describe the formation of fossil fuels.

A: Dead plants and animals buried and compressed over millions of years form coal, oil, and natural gas.

Q149: What is acid rain and its environmental impact?

A: Rain containing sulfuric and nitric acids from pollution, damaging ecosystems and buildings.

Q150: How do renewable energy technologies help combat climate change?

A: They reduce greenhouse gas emissions by using sustainable sources like solar and wind.

Space Science — Advanced Concepts

Q151: Explain how stars produce energy through nuclear fusion.
A: Hydrogen nuclei fuse into helium, releasing vast amounts of energy as light and heat.

Q152: What is the Hertzsprung-Russell diagram and its use?

A: A graph showing star brightness versus temperature, used to classify stars and study their evolution.

Q153: Describe the concept of redshift and what it tells us about the universe.
A: Light from distant galaxies shifts toward red, indicating they are moving away, supporting universe
expansion.

Q154: What are exoplanets and how are they detected?

A: Planets outside our solar system, detected by methods like transit photometry or radial velocity.

Q155: How does the International Space Station (ISS) contribute to science?
A: It allows experiments in microgravity, studying effects on biology, physics, and material science.

Q1 (Biology):
What organelle is known as the “powerhouse” of the cell and why?
A1: The mitochondrion; it produces energy (ATP) through cellular respiration.

Q2 (Chemistry):
How many atoms are present in one molecule of sulfuric acid (H₂SO₄)?
A2: 7 atoms (2 hydrogen + 1 sulfur + 4 oxygen).

Q3 (Physics):
A car accelerates uniformly from rest to 20 m/s in 5 seconds. What is its acceleration?
A3: Acceleration = (final velocity – initial velocity) / time = (20 - 0) / 5 = 4 m/s².

Q4 (Earth Science):
What type of plate boundary is most associated with volcanic eruptions?
A4: Convergent plate boundaries, especially subduction zones.
Q5 (Space Science):
What causes a solar eclipse?
A5: The Moon passes between the Earth and the Sun, blocking the Sun’s light.

Q6 (Biology):
Explain how osmosis differs from diffusion.
A6: Osmosis is the movement of water through a semi-permeable membrane; diffusion is the movement of
any particles from high to low concentration.

Q16 (Biology):
What is the main function of red blood cells?
A16: To carry oxygen from the lungs to body tissues.

Q17 (Chemistry):
What is an isotope?
A17: Atoms of the same element with different numbers of neutrons.

Q18 (Physics):
If a force of 10 N acts on an object causing acceleration of 2 m/s², what is the mass of the object?
A18: Using F=maF = maF=ma, mass m=Fa=102=5m = \frac{F}{a} = \frac{10}{2} = 5m=aF=210=5 kg.

Q19 (Earth Science):

Name the gas primarily responsible for the greenhouse effect.
A19: Carbon dioxide (CO₂).

Q20 (Space Science):

What phenomenon explains the changing phases of the Moon?
A20: The relative positions of the Earth, Moon, and Sun.

Q21 (Biology):
Define photosynthesis in terms of reactants and products.
A21: Photosynthesis uses carbon dioxide and water to produce glucose and oxygen, using sunlight.

Q22 (Chemistry):
What is the law of conservation of mass?
A22: Mass cannot be created or destroyed in a chemical reaction.

Q31 (Biology):
What is the difference between mitosis and meiosis?
A31: Mitosis produces two identical daughter cells for growth and repair; meiosis produces four genetically
different gametes for reproduction.

Q32 (Chemistry):
What happens to the particles of a substance when it melts?
A32: Particles gain energy, vibrate faster, and move from fixed positions to flow freely (solid to liquid).

Q33 (Physics):
What is the formula for calculating pressure? Define each term.
A33: P=FAP = \frac{F}{A}P=AF where PPP = pressure, FFF = force applied, AAA = area over which force
is distributed.

Q34 (Earth Science):

Describe how fossils are formed.
A34: Organisms are buried under sediment; over time, minerals replace organic material, preserving shape.

Q35 (Space Science):

Why do astronauts appear weightless in space?
A35: They are in free fall orbiting Earth, experiencing microgravity.

Q36 (Biology):
What is a food chain? Give an example.
A36: A sequence of organisms each feeding on the previous one; e.g., grass → rabbit → fox.

Q37 (Chemistry):
Explain why salt dissolves in water but not in oil.
A37: Salt is ionic and water is polar, so they interact well; oil is nonpolar and does not dissolve ionic
compounds.

Q38 (Physics):
What is the difference between speed and velocity?
A38: Speed is how fast an object moves; velocity includes speed and direction.

Q39 (Earth Science):

What is the difference between weather and climate?
A39: Weather is short-term atmospheric conditions; climate is long-term average weather patterns.
Q40 (Space Science):
What is the function of the asteroid belt?
A40: It is a region of space between Mars and Jupiter containing many small rocky bodies; it prevents planets
from forming there.

Q41 (Biology):
What role do decomposers play in an ecosystem?
A41: They break down dead organisms, recycling nutrients into the soil.

Q42 (Chemistry):
What is an indicator? Give an example.
A42: A substance that changes color to show pH; e.g., litmus paper turns red in acid and blue in base.

Q43 (Physics):
State Hooke’s Law.
A43: The force needed to stretch or compress a spring is proportional to the displacement, F=kxF = kxF=kx.

Q44 (Earth Science):

Name three types of rocks and how each is formed.
A44: Igneous (cooling magma), sedimentary (compacted sediments), metamorphic (heat and pressure on
existing rocks).

Q45 (Space Science):

What is a black hole?
A45: A region in space with gravity so strong that nothing, not even light, can escape.

Q61 (Biology):
What is the function of the nucleus in a cell?
A61: It controls the cell’s activities and contains genetic material (DNA).

Q62 (Chemistry):
What is the difference between an element and a compound?
A62: An element is a pure substance made of one type of atom; a compound is made of two or more elements
chemically combined.

Q63 (Physics):
What is the formula for speed?
A63: Speed = Distance ÷ Time.
Q64 (Earth Science):
What causes earthquakes?
A64: Sudden movement of tectonic plates along faults.

Q65 (Space Science):

What is the main source of energy for the Earth?
A65: The Sun.

Q66 (Biology):
What is diffusion?
A66: The movement of particles from an area of high concentration to low concentration.

Q67 (Chemistry):
What type of bond holds atoms together in a water molecule?
A67: Covalent bond.

Q68 (Physics):
What type of energy does a stretched rubber band have?
A68: Potential energy.

Q69 (Earth Science):

Name the process by which plants lose water through their leaves.
A69: Transpiration.

Q70 (Space Science):

What is a galaxy?
A70: A large system of stars, gas, and dust held together by gravity.

Q71 (Biology):
What is the function of the respiratory system?
A71: To exchange oxygen and carbon dioxide between the body and the environment.

Q72 (Chemistry):
What is the pH range of acids?
A72: Less than 7.
Q73 (Physics):
What does a simple machine do?
A73: Makes work easier by changing the direction or magnitude of a force.

Q74 (Earth Science):

What is the rock cycle?
A74: The process of rocks changing from one type to another over time.

Q75 (Space Science):

What is a comet’s “tail” made of?
A75: Gas and dust particles pushed away from the comet’s nucleus by the Sun’s radiation.

Q76 (Biology):
Explain how DNA controls protein synthesis.
A76: DNA provides the code for mRNA during transcription; mRNA then carries the code to ribosomes
where proteins are assembled during translation.

Q77 (Chemistry):
Describe the differences between ionic and covalent bonds in terms of electron transfer/sharing and
properties.
A77: Ionic bonds form by transferring electrons between atoms, creating charged ions; they conduct electricity
when dissolved. Covalent bonds share electrons and usually don’t conduct electricity.

Q78 (Physics):
Derive the equation of motion v2=u2+2asv^2 = u^2 + 2asv2=u2+2as and explain each term.
A78: From equations of uniformly accelerated motion: v=u+atv = u + atv=u+at and s=ut+12at2s = ut + \
frac{1}{2}at^2s=ut+21at2. Eliminating time ttt, we get v2=u2+2asv^2 = u^2 + 2asv2=u2+2as where vvv =
final velocity, uuu = initial velocity, aaa = acceleration, sss = displacement.

Q79 (Earth Science):

Explain the theory of plate tectonics and how it accounts for earthquakes and volcanoes.
A79: The Earth’s crust is divided into plates that float on the mantle; their movement causes collisions,
separations, and sliding past one another, resulting in earthquakes and volcanic activity at boundaries.

Q80 (Space Science):

Describe the life cycle of a star similar to our Sun.
A80: It starts as a nebula, forms a protostar, becomes a main sequence star, expands into a red giant, sheds
outer layers as a planetary nebula, and ends as a white dwarf.

Q81 (Biology):
How do mutations in DNA affect organisms?
A81: Mutations change the DNA sequence, potentially altering proteins; effects can be harmful, beneficial, or
neutral, influencing evolution and genetic diseases.

Q82 (Chemistry):
Explain the concept of chemical equilibrium and the effect of changing conditions on equilibrium position.
A82: In a reversible reaction, equilibrium is when forward and reverse rates are equal. Changing
concentration, pressure, or temperature shifts equilibrium according to Le Chatelier’s Principle.

Q83 (Physics):
What is the principle of conservation of momentum? Give an example.
A83: Total momentum before an event equals total momentum after, if no external forces act; e.g., two ice
skaters pushing off each other.

Q84 (Earth Science):

Explain how carbon cycles through the atmosphere, biosphere, and lithosphere.
A84: Carbon moves via processes like photosynthesis, respiration, decomposition, fossil fuel burning, and
volcanic activity, cycling between air, living things, and Earth’s crust.

Q85 (Space Science):

What evidence supports the Big Bang Theory?
A85: Cosmic microwave background radiation, redshift of galaxies, and abundance of light elements like
hydrogen and helium.

Q86 (Biology):
Describe the process of photosynthesis and explain why it is essential for life on Earth.

A86:
Photosynthesis is the process by which green plants use sunlight to convert carbon dioxide and water into
glucose and oxygen. This occurs mainly in the chloroplasts using chlorophyll. The glucose provides energy for
the plant to grow, and the oxygen released supports life for many organisms. Photosynthesis is essential
because it is the primary source of food and oxygen for most living things.

Q87 (Chemistry):
Explain how the periodic table is arranged and how it helps predict the properties of elements.

A87:
The periodic table arranges elements in order of increasing atomic number in rows called periods and columns
called groups. Elements in the same group have similar chemical properties because they have the same
number of electrons in their outer shell. This arrangement helps predict how elements will react and their
physical properties.

Q88 (Physics):
Discuss the different types of energy and give real-life examples where energy is transformed from one type to
another.
A88:
Energy exists in various forms such as kinetic, potential, thermal, chemical, and electrical energy. For
example, in a roller coaster, potential energy at the top converts to kinetic energy as it moves down. In a car,
chemical energy from fuel changes into mechanical energy to move the vehicle.

Q89 (Earth Science):

Explain how natural disasters like earthquakes and volcanic eruptions affect human societies and how we can
reduce their impacts.

A89:
Earthquakes and volcanic eruptions can cause loss of life, damage to buildings, and disrupt communities. They
can destroy infrastructure and cause economic loss. To reduce impacts, we can build earthquake-resistant
structures, have early warning systems, educate the public, and create evacuation plans.

Q90 (Space Science):

Describe how scientists study the universe beyond Earth and why space exploration is important.

A90:
Scientists use telescopes, satellites, and space probes to observe planets, stars, and galaxies. Space exploration
helps us understand the origin of the universe, discover new planets, and develop technology that benefits life
on Earth. It also inspires innovation and international cooperation.

Q91 (Biology):
Discuss how genetic inheritance works and the role of mutations in evolution.

A91:
Genetic inheritance is the process by which parents pass genes to their offspring through DNA. Each gene
carries instructions for traits. Mutations are changes in DNA sequences that can introduce new traits. While
some mutations may be harmful, others can provide advantages, helping species adapt and evolve over time
through natural selection.

Q92 (Chemistry):
Describe an experiment you could do to investigate the effect of temperature on the rate of a chemical
reaction.

A92:
One could react hydrochloric acid with magnesium and measure how fast bubbles of hydrogen gas form at
different temperatures. By heating the acid to various temperatures and timing the reaction, it would show that
higher temperatures increase the reaction rate because particles move faster and collide more often.

Q93 (Physics):
Explain how Newton’s laws of motion apply to everyday activities, such as riding a bicycle.

A93:
Newton’s first law explains that a bicycle will stay still or keep moving unless a force acts on it. The second
law shows that pushing harder on pedals makes the bike accelerate. The third law means the bike pushes back
on the ground as the rider pushes on the pedals, allowing movement.
Q94 (Earth Science):
Discuss the impact of human activities on the Earth’s climate and suggest ways to promote sustainability.

A94:
Human activities like burning fossil fuels and deforestation release greenhouse gases, causing global warming
and climate change. To promote sustainability, we can reduce emissions by using renewable energy, plant
trees, recycle, and conserve water and energy.

Q95 (Space Science):

Explain the life cycle of a star and what happens to stars after they die.

A95:
Stars form from clouds of gas and dust called nebulae. They enter the main sequence phase where they fuse
hydrogen into helium. Depending on their size, stars may become red giants or supergiants. After that, smaller
stars turn into white dwarfs, while massive stars explode as supernovae, leaving neutron stars or black holes.

Q96 (Biology):
Explain the process of cell division and why it is important for living organisms.

A96:
Cell division is the process where a single cell divides into two new cells. In mitosis, the cell copies its DNA
and splits to produce identical daughter cells for growth and repair. In meiosis, cells divide to produce gametes
with half the DNA, which is important for sexual reproduction and genetic diversity. Cell division is crucial
for development, healing, and reproduction.

Q97 (Chemistry):
Describe how acids and bases react and give examples of their uses in everyday life.

A97:
Acids release hydrogen ions (H⁺) in water, while bases release hydroxide ions (OH⁻). When acids and bases
react, they neutralize each other to form salt and water. For example, vinegar (acid) is used in cooking, and
baking soda (base) is used in baking and cleaning.

Q98 (Physics):
What is thermal energy and how does heat transfer occur? Give examples.

A98:
Thermal energy is the total energy of particles in a substance due to their motion. Heat transfer occurs through
conduction (direct contact), convection (fluid movement), and radiation (electromagnetic waves). For
example, conduction happens when a metal spoon gets hot in a pot, convection in boiling water, and radiation
from the Sun warming the Earth.

Q99 (Earth Science):

How do human activities contribute to soil erosion, and what can be done to prevent it?
A99:
Activities like deforestation, overgrazing, and farming without proper soil management remove protective
vegetation and loosen soil, leading to erosion by wind and water. Prevention methods include planting cover
crops, building terraces, and reforesting to protect and stabilize soil.

Q100 (Space Science):

Explain the reasons for seasons on Earth.

A100:
Seasons occur because Earth is tilted on its axis as it orbits the Sun. When the Northern Hemisphere tilts
toward the Sun, it experiences summer with more direct sunlight and longer days. When it tilts away, it
experiences winter with less direct sunlight and shorter days. The Southern Hemisphere experiences opposite
seasons at the same time.

Q101 (Biology):
Describe how the structure of a leaf is adapted for photosynthesis.

A101:
A leaf has a large surface area to absorb sunlight and a thin shape to allow gases to diffuse easily. The upper
layer has a waxy cuticle to reduce water loss. Inside, chloroplasts in the palisade cells capture light energy.
The stomata on the underside open and close to let carbon dioxide in and oxygen out, aiding gas exchange
necessary for photosynthesis.

Q102 (Chemistry):
What is the difference between physical and chemical changes? Give examples.

A102:
Physical changes alter the form or appearance of a substance without changing its composition, such as
melting ice or tearing paper. Chemical changes result in the formation of new substances with different
properties, like burning wood or rusting iron.

Q103 (Physics):
Explain how sound travels and why it cannot travel through a vacuum.

A103:
Sound travels as vibrations through particles in a medium like air, water, or solids. The particles vibrate and
pass the energy along. In a vacuum, there are no particles to carry vibrations, so sound cannot travel.

Q104 (Earth Science):

Discuss the water cycle and its importance for life on Earth.

A104:
The water cycle involves evaporation of water from oceans and lakes, condensation forming clouds,
precipitation as rain or snow, and runoff returning water to bodies of water. This continuous movement
distributes fresh water, supports plant growth, regulates climate, and sustains all living organisms.
Q105 (Space Science):
What are black holes, and how are they detected by astronomers?

A105:
Black holes are regions of space with gravity so strong that nothing can escape, not even light. They are
detected by observing the effects on nearby stars and gas, such as high-speed orbiting of stars or X-rays
emitted when matter falls into the black hole.

Q106 (Biology):
How does the human circulatory system function to transport materials around the body?

A106:
The circulatory system uses the heart to pump blood through blood vessels. Blood carries oxygen and nutrients
to cells and removes waste products like carbon dioxide. The system includes arteries, veins, and capillaries
that ensure efficient transport throughout the body.

Q107 (Chemistry):
Explain the concept of conservation of mass in chemical reactions.

A107:
The conservation of mass states that matter is neither created nor destroyed during a chemical reaction. The
total mass of reactants equals the total mass of products, meaning atoms are rearranged but their total number
stays the same.

Q108 (Physics):
What factors affect the rate of cooling of an object?

A108:
Factors include the temperature difference between the object and surroundings, surface area (larger area cools
faster), the material’s thermal conductivity, and whether the object is in air, water, or vacuum.

Q109 (Earth Science):

How do fossils provide evidence for evolution?

A109:
Fossils show how organisms have changed over time by preserving remains of past life forms. Comparing
fossils from different layers reveals gradual changes and the appearance of new species, supporting the theory
of evolution.

Q110 (Space Science):

Why is the study of the solar system important for understanding Earth’s place in the universe?

A110:
Studying the solar system helps us learn about the formation and evolution of planets, the conditions that make
life possible, and the effects of solar activity on Earth. It gives context to Earth’s environment and helps in
searching for life elsewhere.
Q111 (Biology):
Explain how enzymes work and why they are important in living organisms.

A111:
Enzymes are proteins that act as biological catalysts, speeding up chemical reactions without being used up.
They lower the activation energy needed for reactions. Enzymes are important because they allow vital
processes like digestion and metabolism to occur efficiently at body temperature.

Q112 (Chemistry):
What is an isotope, and how can isotopes of the same element be different?

A112:
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
This means they have different mass numbers but similar chemical properties. Some isotopes are stable, while
others are radioactive.

Q113 (Physics):
Describe the law of conservation of energy and give an example.

A113:
The law of conservation of energy states that energy cannot be created or destroyed, only transformed from
one form to another. For example, in a pendulum, potential energy converts to kinetic energy and back, but
total energy remains constant.

Q114 (Earth Science):

What is soil formation, and what factors influence it?

A114:
Soil forms from the weathering of rocks and the decay of organic matter. Factors influencing soil formation
include climate, organisms, parent rock material, topography, and time. These factors determine soil type and
fertility.

Q115 (Space Science):

Explain how satellites help us learn about Earth and space.

A115:
Satellites orbit Earth and collect data on weather, climate, communications, and natural disasters. Space
telescopes observe stars, galaxies, and other celestial phenomena without atmospheric interference, providing
clearer images than ground-based telescopes.

Q116 (Biology):
How do vaccines help protect the body from diseases?

A116:
Vaccines contain weakened or inactive parts of pathogens that stimulate the immune system to produce
antibodies. This prepares the body to fight the real pathogen if exposed, providing immunity without causing
illness.

Q117 (Chemistry):
What is an exothermic reaction? Give an example.

A117:
An exothermic reaction releases heat to the surroundings. For example, combustion of gasoline in an engine
releases heat and light energy.

Q118 (Physics):
How does light behave when it passes through different materials?

A118:
Light can be reflected, refracted, or absorbed depending on the material. When passing from one medium to
another, it bends (refraction) due to change in speed. Mirrors reflect light, while some materials absorb light,
converting it to heat.

Q119 (Earth Science):

What causes tides on Earth?

A119:
Tides are caused mainly by the gravitational pull of the Moon and the Sun on Earth’s oceans. The Moon’s
gravity pulls water toward it, creating high tides, while areas perpendicular experience low tides.

Q120 (Space Science):

Describe the main differences between terrestrial planets and gas giants.

A120:
Terrestrial planets, like Earth and Mars, are rocky with solid surfaces, smaller in size. Gas giants, like Jupiter
and Saturn, are much larger, mostly made of gases like hydrogen and helium, and lack solid surfaces.

Q121 (Biology):
Explain the role of mitochondria in cells and why they are often called the “powerhouses” of the cell.

A121:
Mitochondria are organelles where cellular respiration takes place. They convert glucose and oxygen into
energy in the form of ATP (adenosine triphosphate), which cells use to perform activities. They’re called the
“powerhouses” because they provide the energy needed for cell functions.

Q122 (Chemistry):
How does the structure of an atom relate to the properties of elements?

A122:
An atom’s structure—number of protons, neutrons, and electrons—determines the element’s identity and
properties. The arrangement of electrons, especially in the outer shell, influences how atoms bond and react
chemically.

Q123 (Physics):
What factors influence the period of a pendulum, and how can this be experimentally investigated?

A123:
The period of a pendulum depends on its length and gravity, but not on mass or amplitude (for small swings).
This can be investigated by timing swings of pendulums of different lengths and plotting the results.

Q124 (Earth Science):

Discuss the greenhouse effect and its significance for Earth’s climate.

A124:
The greenhouse effect occurs when gases like carbon dioxide trap heat in Earth’s atmosphere, keeping the
planet warm enough to support life. However, excess greenhouse gases from human activity enhance this
effect, causing global warming and climate change.

Q125 (Space Science):

How do astronauts survive and conduct experiments in space?

A125:
Astronauts survive by living in spacecraft with controlled air, water, and food supply, and protection from
radiation. They conduct experiments in microgravity to study physics, biology, and material science that can’t
be done on Earth.

Q126 (Biology):
Explain the difference between aerobic and anaerobic respiration.

A126:
Aerobic respiration requires oxygen and produces more energy by completely breaking down glucose into
carbon dioxide and water. Anaerobic respiration occurs without oxygen, producing less energy and substances
like lactic acid or alcohol.

Q127 (Chemistry):
Why do elements in the same group of the periodic table have similar chemical properties?

A127:
Elements in the same group have the same number of electrons in their outermost shell, which determines
their chemical reactivity and bonding behavior, causing them to have similar properties.

Q128 (Physics):
Explain how lenses form images and differentiate between convex and concave lenses.
A128:
Convex lenses converge light rays to form real or virtual images depending on object distance, used in
magnifying glasses. Concave lenses diverge light rays, producing only virtual, smaller images, used in
eyeglasses for nearsightedness.

Q129 (Earth Science):

What are renewable and non-renewable resources? Give examples and explain why conservation is
important.

A129:
Renewable resources can be replenished naturally, like solar and wind energy. Non-renewable resources, like
coal and oil, exist in finite amounts. Conservation is important to avoid depletion and protect the environment.

Q130 (Space Science):

How does the Doppler effect help astronomers understand the movement of galaxies?

A130:
The Doppler effect causes the wavelength of light from galaxies to shift depending on their motion. If a galaxy
moves away, its light shifts toward red (redshift), showing the universe is expanding.

Q131 (Biology):
Describe the structure and function of DNA and explain how it controls inheritance.

A131:
DNA is a double helix made of nucleotides containing sugar, phosphate, and four bases (A, T, C, G). It stores
genetic information in the sequence of bases, which codes for proteins. During reproduction, DNA is copied
and passed to offspring, controlling inherited traits.

Q132 (Chemistry):
What is the difference between ionic and covalent bonds? Provide examples.

A132:
Ionic bonds form when electrons are transferred from one atom to another, creating charged ions that attract
each other (e.g., sodium chloride). Covalent bonds form when atoms share electrons (e.g., water). Ionic
compounds tend to have high melting points and conduct electricity when dissolved.

Q133 (Physics):
Explain the principle of conservation of momentum and provide a real-world example.

A133:
The conservation of momentum states that in a closed system, total momentum before and after an event is
constant. For example, in a collision between two ice skaters pushing off each other, the total momentum stays
the same but is redistributed between them.

Q134 (Earth Science):

How do tectonic plates cause earthquakes and volcanoes?
A134:
Tectonic plates move slowly on Earth’s surface. When they collide, slide past, or move apart, stress builds and
is released as earthquakes. Volcanoes form where plates diverge or converge, allowing magma to reach the
surface.

Q135 (Space Science):

Discuss the importance of the Hubble Space Telescope in modern astronomy.

A135:
The Hubble Space Telescope orbits above Earth’s atmosphere, avoiding distortion, and captures high-
resolution images of distant galaxies, nebulae, and stars. It has helped measure the universe’s expansion and
discover exoplanets, transforming our understanding of space.

Q136 (Biology):
Explain the relationship between structure and function in animal cells.

A136:
Animal cells have specialized structures like the nucleus (controls activities), mitochondria (energy
production), and ribosomes (protein synthesis). Each organelle’s structure suits its function, enabling the cell
to survive and work efficiently.

Q137 (Chemistry):
What is an acid-base indicator and how does it work?

A137:
An acid-base indicator changes color depending on the pH of a solution. For example, litmus turns red in acid
and blue in base. This happens because the indicator molecules react differently with hydrogen or hydroxide
ions.

Q138 (Physics):
Describe how electric circuits work and explain the role of resistors.

A138:
Electric circuits allow electrons to flow through conductors like wires. A power source pushes electrons, and
resistors control the current by providing resistance, protecting components and regulating voltage.

Q139 (Earth Science):

How does deforestation affect biodiversity and the climate?

A139:
Deforestation reduces habitats, leading to loss of plant and animal species (biodiversity). It also increases
carbon dioxide levels by reducing trees that absorb CO2, contributing to climate change and global warming.
Q140 (Space Science):
What are exoplanets and how do scientists detect them?

A140:
Exoplanets are planets outside our solar system. Scientists detect them by observing stars’ dimming when a
planet passes in front (transit method) or by measuring star wobbles caused by gravitational pull (radial
velocity method).

Q141 (Biology):
Describe how natural selection leads to evolution in a population.

A141:
Natural selection occurs when individuals with traits better suited to their environment survive and reproduce
more successfully. Over generations, these advantageous traits become more common, causing the population
to evolve.

Q142 (Chemistry):
Explain the process of electrolysis and give an example of its application.

A142:
Electrolysis is the use of electric current to break down a compound into its elements. For example,
electrolysis of water splits it into hydrogen and oxygen gases.

Q143 (Physics):
What is the difference between speed and velocity?

A143:
Speed is how fast an object moves regardless of direction, while velocity includes both speed and direction.
Velocity is a vector quantity, speed is a scalar.

Q144 (Earth Science):

How does weathering differ from erosion?

A144:
Weathering is the breakdown of rocks into smaller pieces by physical, chemical, or biological means. Erosion
is the movement of these broken-down materials by wind, water, or ice.

Q145 (Space Science):

What causes a solar eclipse and how often do they occur?

A145:
A solar eclipse happens when the Moon passes between Earth and the Sun, blocking sunlight. They occur
roughly 2 to 5 times a year but are visible only from specific areas.

Q146 (Biology):
What role do ribosomes play in a cell?
A146:
Ribosomes are the sites of protein synthesis, where amino acids are assembled into proteins according to
instructions from DNA.

Q147 (Chemistry):
Describe what a catalyst does in a chemical reaction.

A147:
A catalyst speeds up a chemical reaction without being consumed by lowering the activation energy needed
for the reaction.

Q148 (Physics):
What is inertia and how does it affect moving objects?

A148:
Inertia is the tendency of an object to resist changes in its motion. A moving object will keep moving at the
same speed and direction unless acted upon by a force.

Q149 (Earth Science):

What are renewable energy sources and why are they important?

A149:
Renewable energy sources come from natural processes that are constantly replenished, like solar, wind, and
hydro power. They are important because they reduce pollution and dependence on fossil fuels.

Q150 (Space Science):

Explain the significance of the Big Bang theory.

A150:
The Big Bang theory explains that the universe began as a small, hot, dense point and has been expanding ever
since. It provides the foundation for understanding the origin and evolution of the universe.

Q151 (Biology):
How does the process of photosynthesis benefit heterotrophic organisms?

A151:
Photosynthesis produces glucose and oxygen. Heterotrophic organisms rely on glucose as a food source for
energy and oxygen for respiration, making photosynthesis essential for their survival.

Q152 (Chemistry):
What are the three states of matter, and how do their particle arrangements differ?

A152:
Solids have tightly packed particles in fixed positions, liquids have closely packed but movable particles, and
gases have widely spaced particles moving freely.
Q153 (Physics):
What is the difference between weight and mass?

A153:
Mass is the amount of matter in an object and does not change. Weight is the force of gravity acting on that
mass and can vary depending on location.

Q154 (Earth Science):

Describe the rock cycle.

A154:
The rock cycle is the process by which rocks change from one type to another through melting, cooling,
erosion, sedimentation, and heat and pressure.

Q155 (Space Science):

Why does the Moon appear to change shape over a month?

A155:
The Moon’s phases occur because of its position relative to Earth and the Sun, showing different portions of
its lit half as it orbits Earth.

Q156 (Biology):
Explain how the immune system protects the body from infection.

A156:
The immune system detects and attacks pathogens using white blood cells, antibodies, and other defenses,
preventing disease and helping the body recover.

Q157 (Chemistry):
Define an element and a compound.

A157:
An element is a pure substance made of only one kind of atom. A compound consists of two or more different
elements chemically bonded together.

Q158 (Physics):
What is potential energy? Give an example.

A158:
Potential energy is stored energy due to an object’s position or condition. For example, water held behind a
dam has potential energy.
Q159 (Earth Science):
What causes seasons on Earth?

A159:
Seasons are caused by Earth’s axial tilt and orbit around the Sun, resulting in varying sunlight angles and
daylight length throughout the year.

Q160 (Space Science):

How do astronauts experience weightlessness in space?

A160:
Astronauts experience weightlessness because they are in free-fall orbit around Earth, continuously falling but
moving forward fast enough to keep missing the surface.

Q1 (Biology):
Which organelle is known as the “powerhouse of the cell”?
A) Nucleus
B) Mitochondria
C) Ribosome
D) Chloroplast

Answer: B) Mitochondria

Q2 (Chemistry):
What is the chemical formula of water?
A) CO₂
B) H₂O
C) O₂
D) NaCl

Answer: B) H₂O

Q3 (Physics):
What is the unit of force?
A) Joule
B) Newton
C) Watt
D) Pascal

Answer: B) Newton

Q4 (Earth Science):
Which layer of the Earth is liquid?
A) Crust
B) Inner core
C) Outer core
D) Mantle
Answer: C) Outer core

Q5 (Space Science):
Which planet is known as the “Red Planet”?
A) Venus
B) Mars
C) Jupiter
D) Saturn

Answer: B) Mars

Q6 (Biology):
Photosynthesis mainly occurs in which part of the plant?
A) Roots
B) Stem
C) Leaves
D) Flowers

Answer: C) Leaves

Q7 (Chemistry):
What type of bond is formed when atoms share electrons?
A) Ionic bond
B) Covalent bond
C) Metallic bond
D) Hydrogen bond

Answer: B) Covalent bond

Q8 (Physics):
What happens to the speed of light when it passes from air to water?
A) It increases
B) It decreases
C) It stays the same
D) It stops

Answer: B) It decreases

Q9 (Earth Science):
Which process breaks down rocks into smaller pieces?
A) Erosion
B) Weathering
C) Melting
D) Deposition

Answer: B) Weathering
Q10 (Space Science):
What force keeps planets in orbit around the Sun?
A) Magnetic force
B) Gravity
C) Friction
D) Electromagnetic force

Answer: B) Gravity

Q11 (Biology):
Which of the following is NOT a function of the cell membrane?
A) Protect the cell
B) Control what enters and leaves the cell
C) Produce energy for the cell
D) Maintain homeostasis

Answer: C) Produce energy for the cell

Q12 (Chemistry):
What is the pH of a neutral solution?
A) 0
B) 7
C) 14
D) 3

Answer: B) 7

Q13 (Physics):
What is the acceleration due to gravity on Earth?
A) 9.8 m/s²
B) 10 m/s²
C) 8.9 m/s²
D) 12 m/s²

Answer: A) 9.8 m/s²

Q14 (Earth Science):

Which of the following is a fossil fuel?
A) Solar energy
B) Wind energy
C) Coal
D) Hydropower

Answer: C) Coal
Q15 (Space Science):
What is the main gas in the Sun?
A) Oxygen
B) Hydrogen
C) Nitrogen
D) Carbon dioxide

Answer: B) Hydrogen

Q16 (Biology):
Which blood cells help fight infection?
A) Red blood cells
B) White blood cells
C) Platelets
D) Plasma

Answer: B) White blood cells

Q17 (Chemistry):
Which of the following is an example of a physical change?
A) Rusting of iron
B) Burning of wood
C) Melting of ice
D) Baking a cake

Answer: C) Melting of ice

Q18 (Physics):
Which law states that for every action, there is an equal and opposite reaction?
A) Newton’s First Law
B) Newton’s Second Law
C) Newton’s Third Law
D) Law of Conservation of Energy

Answer: C) Newton’s Third Law

Q19 (Earth Science):

Which instrument is used to measure earthquakes?
A) Barometer
B) Seismograph
C) Thermometer
D) Anemometer

Answer: B) Seismograph
Q20 (Space Science):
Which galaxy is closest to the Milky Way?
A) Andromeda Galaxy
B) Whirlpool Galaxy
C) Sombrero Galaxy
D) Pinwheel Galaxy

Answer: A) Andromeda Galaxy

Q21 (Biology):
What is the basic unit of life?
A) Organ
B) Cell
C) Tissue
D) Organ system

Answer: B) Cell

Q22 (Chemistry):
Which subatomic particle has a positive charge?
A) Electron
B) Neutron
C) Proton
D) Ion

Answer: C) Proton

Q23 (Physics):
Which of the following is a vector quantity?
A) Speed
B) Mass
C) Velocity
D) Temperature

Answer: C) Velocity

Q24 (Earth Science):

What type of rock is formed from cooled lava?
A) Sedimentary
B) Metamorphic
C) Igneous
D) Fossil

Answer: C) Igneous

Q25 (Space Science):

Which planet is the largest in our solar system?
A) Earth
B) Jupiter
C) Saturn
D) Neptune

Answer: B) Jupiter

Q26 (Biology):
Which process produces gametes?
A) Mitosis
B) Meiosis
C) Fertilization
D) Photosynthesis

Answer: B) Meiosis

Q27 (Chemistry):
What is the smallest unit of an element that retains its properties?
A) Molecule
B) Atom
C) Ion
D) Compound

Answer: B) Atom

Q28 (Physics):
Energy can be converted from one form to another but cannot be created or destroyed. This is known as:
A) Law of Inertia
B) Law of Gravity
C) Law of Conservation of Energy
D) Newton’s Second Law

Answer: C) Law of Conservation of Energy

Q29 (Earth Science):

Which gas makes up most of Earth’s atmosphere?
A) Oxygen
B) Nitrogen
C) Carbon dioxide
D) Hydrogen

Answer: B) Nitrogen

Q30 (Space Science):

What is the main source of energy for the Earth?
A) Moon
B) Stars
C) Sun
D) Planets

Answer: C) Sun