5th General Science

Chapter 1 Classification of living things

i. Define biodiversity
Ans. The variety of plants and animals on a particular place is called biodiversity.
ii. State the importance of classification
Ans. Classification make it easier to study the organism.
iii. Write difference between (a) worms and insects (b) amphibians and reptiles
Ans. Insects have legs while worms do not have. Similarly, Amphibians have moist and loose skins while reptiles have
thick, coarse and dry skin.
iv. What is the similarity between fungi and animals?
Ans. Fungi and animals do not have chlorophyll and cannot make their own food.
v. Write one characteristic and example of Monera and Protista.
Ans. Monera are unicellular like bacteria. While Protista have chlorophyll like amoeba.
Constructed response questions:
i. Some animals have skeleton of cartilage such as Shark and Sting Ray. They feed on other animals by predation.
What is the importance of cartilage in their life?
Ans. Cartilage make their bodies flexible enough to move and hunt easily.
ii. Why the body of Zebra has white and black stripes?
Ans. The black and which strips on the body of zebras help in protection and thermoregulation.
iii. Why are the ears of elephant large?
Ans. Large ears of the elephants help them to maintain their body temperature.
iv. Investigate about the factors responsible for the extinction of biodiversity
Ans. Deforestation and excessive hunting are the reasons of the extinction of biodiversity.
v. Give an example of extinct and endanger animals. Investigate what types of animals are mostly likely to be
extinct?
Ans. Dodo has been extinct and panda is endangered. Similarly, Markhor is mostly likely to be extinct.
Chapter 2 Microorganism
i. What is a pathogen? How does it enters in the bodies of organisms?
Ans. Pathogens are microorganism that cause diseases. They enter the body through air, water, food, animals and
direct contact.
ii. Why some bacteria and fungi are called decomposers?
Ans. Some bacteria and fungi are decomposers because they break the dead bodies into simple components.
iii. Write two benefits and two harmful effects of bacteria?
Ans. Decomposition and making of yogurt are the benefits while spoiling of food and spreading of diseases.
iv. How does the microorganism (yeast) work to soften and rise dough of flour?
Ans. Yeast releases carbon dioxide which is absorbed by gluten and as a result dough is raised.
v. How does a mosquito transmit a disease?
Ans. Mosquito sucks blood from the infected person and transmit it to the healthy person through bite.
vi. The soil of forest and hot climate is always hot and moist, whereas the soil of forest of cold climate is cold and
dry. Out of these two areas where the decomposition of fallen leaves will happen more quickly? Explain.
Ans. The decomposition leaves in hot climate will occur quickly because the rate of decomposition increases with
increase in temperature.
vii. “All microorganism are harmful and spread diseases.” Prove that this idea is incorrect.
Ans. Some bacteria help in digestion and absorption. Yeast raises dough in flour.
viii. Many people use antibacterial soap to kill the bacteria present on their hands. But due to excessive use of soap,
the chance of getting infection increases instead of decreasing. Why does it happen?
Ans. Excessive use of soap remove healthy bacterial and natural oil from skin and hence causes diseases.
Unit 3 Flowers and seeds
1. Can you tell the names and functions of the four parts of a flower?
Ans. The four parts of a flower are sepals, petals, stamens and carpel. Sepal protects the internal structure, petals
attracts insects and birds, stamens and carpels are reproductive parts.
2. How you will compare self-pollination and cross-pollination?
Ans. In self-pollination, the transfer of grains occurs in the same flower or plants while in cross-pollination it occurs
with the flowers of other plants.
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 3. Compare gram and maize seed?
Ans. A maize seed is monocot, oval in shape, having endosperm with thin seed coat. A gram seed is dicot, conical in
shape and contain micropyle with thick seed coat.
4. Define reproduction
Ans. Reproduction is the process by which organisms produce new organisms of their own kind.
5. Label the given picture?
6. If all the insects become instinct, what will be its effect on flowering plants?
Ans. If all the insect become instinct, then there will be no cross-pollination and the number of plants would decrease.
Unit 4 Environmental pollution
1. Write three causes of air pollution.
Ans. Forest fire, vehicle smoke and industrial smoke are the causes of air pollution.
2. What are the four effects of pollution on life?
Ans. Pollution spread disease, pollutes water, increases in garbage and public expenses.
3. What is green-house effect?
Ans. Gases in the air allow sunlight to reach the earth but do not leave the heat and makes the Earth hot.
4. What will be the effects of global warming?
Ans. Global warming causes more rain and floods.
5. Write three ways of preventive measures to reduce pollution.
Ans. Growing trees, reducing smoke and proper dispose of waste can reduce pollution.
6. What is the relationship between disease and pollution?
Ans. Use of polluted air, water and food are the root causes of many diseases.
7. Identify bio-degradable and non-biodegradable material present in your environment
Ans. Fruits, vegetable, grain and meat are biodegradable while polythene bags, plastic bottles and glass dishes are
non-biodegradable.
8. What is the main cause of pollution?
Ans. Human being is the main cause of pollution.
9. Why the government of Pakistan has banned the use of polythene bags?
Ans. Polythene bags are non-biodegradable and a major cause of pollution and hence banned by the Government of
Pakistan.
10. If it is written D2W on polythene bags then why there is no ban on the use of such bags.
Ans. D2W polythene bags are biodegradable. Therefore it could be used.

Chapter 5 Physical and Chemical changes in matter

1. Explain evaporation by giving example from everyday life
Ans. The change of water into vapor is called evaporation e.g. drying up of wet clothes
2. Define condensation
Ans. The change of liquid into gas is called condensation.
3. What is rusting? And which type of change is this?
Ans. The change which occur on the surface of iron due to action of oxygen or water is called rusting. It is a physical
change.
4. Give an example of chemical change in which carbon dioxide is produced?
Ans. Burning of paper is a chemical change in which carbon dioxide is produced.
5. Explain the three states of matter and their interconversion.
Ans. The three states matter solid, liquid and gas interconvert like from ice to water and then vapour.
6. Why the formation of fertilizer from the leave is a chemical change?
Ans. In fertilizers, the shape and appearance of leaves are totally changed and hence it is a chemical change.
7. On mixing vinegar into baking soda and boiling water bubbles are produced. Out of the two one is chemical
change and the other one is a physical change. Explain
Ans. On mixing vinegar into baking soda, a gas is released which is a chemical change. In boiling of water, water take
the form of gas and evaporate which is a physical change.
8. A student weighs a piece of ice and then allow it to melt. In your opinion what will be the weight of water and
why?
Ans. The weight of ice and water will be same. Melting of ice is a physical change.
Chapter 6 Light and Sound
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 1. What is transparent object? Write the name of three transparent objects.
Ans. The objects through which light can pass completely are called transparent e.g. glass, window pane etc.
2. When is your shadow the shortest and longest in the sunlight?
Ans. Shadow is longest at morning and evening while shortest in the noon.
3. The moon is non-luminous like our earth. How does it look luminous to us?
Ans. The moon reflects the sunlight and it looks luminous.
4. Can you be the winner while running with your shadow if the sun is at your back? Give the reason also.
Ans. The race could not be win as the shadow is formed in the opposite direction.
5. When a train is moving away from you, will the intensity of its sound increase or decrease?
Ans. The intensity of sound decease with increase in distance.
6. “Ears are raised” is a phrase in Urdu. The ears of some animals such as hare are actually raised up? When and
why?
Ans. Hare raise it ears to release excess of body heat.
7. The wood and coal are naturally non-luminous objects. Can they be made luminous? How?
Ans. Wood and coal can be made luminous through burning them.
8. How can you compare the speed of light and speed of sound coming from the lightening?
Ans. The speed of light is quite higher than the speed sound that is why lightening is observed before its sound.
9. Have you seen the ears of frog and fish? How do these animals hear sounds?
Ans. Frog and fish listen through their sensitive skins.
Chapter 7 Electricity and Magnetism
1. Why does a bulb lights up in a close circuit?
Ans. A bulb lights up in a close due to flow of current.
2. You are given a bulb. What other components are required to light it up?
Ans. Besides bulb, battery, wires and switch are required to light it up.
3. Why an iron nail stuck to a magnet attracts another nail?
Ans. The iron nail stuck to a magnet becomes magnetized and attracts the other nails.
4. How are direction found while using a magnetic compass?
Ans. The needle of the compass always stay on the north-south direction and hence indicate the direction.
5. A balloon is charged by rubbing it with a woolen cloth. Why does it stick to the wall when brought near it?
Ans. A rubbed balloon stuck to the wall due to having opposite charges.
6. Two ring magnets are shown on a woolen stand. The upper magnet rises up and is suspended in are as shown in
the figure. (a) Why does the upper magnet float in the air? (b) Label the N and S-poles of the magnet.
Ans. (a)The upper magnet float in the air due to like poles as like poles repel each other.
(b) As per diagrams, the inner sides of the magnets are South Pole while the outer sides are north poles.
7. There is a bar magnet without any indication. How will you identify its south pole?
Ans. A freely suspend the bar magnet always stay in the North-South direction. The end that points to the north is the
South Pole.
8. There are three similar metal bars. One is magnet, the second one is that of iron and third bar is of aluminum.
How would you identify each bar?
Ans. A bar which when freely suspended, stays in north-south direction is magnet. The bar which is attracted by
magnet is iron bar. The third bar which is not attracted by the magnet is aluminum.
9. A plastic comb charged with a woolen clothe is touched with an iron key. What do you observe? Give an example
of similar phenomenon in daily life.
Ans. Light is produced when a charged comb is touched with an iron key.
Chapter 8 Structure of the Earth
1. Name the outer layer of the earth. What is its importance in our life?
Ans. The outer layer of the Earth is crust. It contains water, soil and other minerals.
2. Which soil is useful to make pottery? What are its properties?
Ans. Clay soil is useful to make pottery. It is soft and sticky.
3. Which matter is obtained from the decayed plants and animals?
Ans. Humus is obtained from the decayed plants and animals.
4. How much part of the earth’s surface consist of oceans. Why we cannot drink sea water?
Ans. 70% of the earth’s surface consists of oceans. The sea water is salty and cannot be drunk.
5. Where the water is found in the form of solid, liquid and gas (vapours)?
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Ans. The surface of frozen lacks are solid, which also emit gas i.e. vapours. The water below is liquid.
6. Which soil is used to plaster the houses in village? Which property of the soil is useful to do so?
Ans. Clay soil is used to plaster houses in village. The stickiness of the clay is useful to do so.
7. How does the plant roots and other creature inside the earth respire?
Ans. The soil contain air which is essential for respiration.
8. You have heard the devastation of flood. What is it reason? How the surplus water of the flood can be made
useful.
Ans. Heavy rain and deforestation are the reason of flood. The surplus water may be stored in dams to make it useful.
Chapter 9 Space and Satellite
1. Write three benefits which we get from artificial satellite.
Ans. Artificial satellite helps in transmission, communication and predicting changes in a weather.
2. Moon is satellite of earth. Is the earth also the satellite of some bigger object? What is that object?
Ans. Earth is the satellite of Sun.
3. Why does a geo-stationary satellite appear to be stationary?
Ans. The geo-stationary satellite revolves at the speed of Earth and hence seems to be stationary.
4. Why do the astronauts wear space dress? What are its benefits?
Ans. Space dress helps in maintaining temperature, gravity and taking oxygen.
5. Why a telescope installed on a satellite can take more clear photographs than from the Earth surface?
Ans. A telescope installed on a satellite is quite closer to the earth and hence take clear photographs.
6. What provide the force needed to keep the artificial satellite moving around the Earth? Indicate its direction on
the two satellites shown in the given figure.
Ans. The Earth provide centripetal force to keep the artificial satellite moving around the Earth. The force is directed
toward the Earth.
7. Astronauts have to face a lot of problems in space. Can you name some of these problems?
Ans. Astronaut face the health problems, lack of gravity, closed environment, isolation etc.
8. How to do the astronaut respire in your opinion?
Ans. Astronauts respire through oxygen tanks or electrolysis of water.
9. Why cannot you pour water in a glass in space?
Ans. Water cannot be poured in a glass due to lack of gravity.
10. Investing in library or through internet what types of experiments are performed in the space station that cannot
be done while living on the Earth.
Ans. Experiments involving microgravity are done in the space.
Chapter 10 Technology in Everyday Life
1. List down the material needed to make a model of Foot Bridge.
Ans. Skewers, ice cream sticks, paper, thread and glue are needed to make a model of Foot Bridge.
2. What is the difference between the functions of sprit level and plumb line?
Ans. Spirit level is used for horizontal while plumb line is used for vertical surfaces.
3. What is an LED lamp?
Ans. LED are the tiny light emitting bulbs.
4. You have to install a picture frame on the wall. How it can be kept straight horizontally as well as vertically?
Ans. A picture may be kept straight horizontally and vertically through spirit level and plumb line.
5. What is meant by first aid?
Ans. First aid is a temporary care given to a person who has got sudden illness or injury.
6. What sort of tools and equipment’s are required to make a wooden model?
Ans. A saw, hammer, nails, spirit level, glue etc. are required to make a wooden model.
7. How does a musical instrument produce a sound?
Ans. Musical sound is produced due to vibration.
8. Why is it necessary to join long wires of LED together and short wires together while preparing a light string?
Ans. The long wire show positive and short wires indicate negative ends to be connected with the respective
terminals.