CBSE Class 3 Science ISO Olympiad MCQs with Answers Set A

1. Matter is anything that occupies space and has mass. Which one of the following is correct about air?
(a) Air is not a matter
(b) Air is a matter
(c) Air can partially be a matter
(d) All of these
Answer : (b) Air is a matter as it occupiesspace and has mass.

2. Green plants make their own food.
They are called?
(a) heterotrophs
(b) autotrophs
(c) saprophytes
(d) all of these
Answer : (b) Green plants make their own food and hence are called autotrophs.

3. Which part of the body of the car comes from a plant?

(a) 1
(b) 2
(c) 3
(d) 4
Answer : (d) 4 is tyre, made up of rubber. We get rubber from plants

4. 1. Water flows from one place to another.
2. Clouds moves from one place to another.
3. The leaves of “touch me not” plant closes after touching.
4. Flowers of the sunflower plants move in the direction of sunWhich of the above mentioned activities shows movement in living things?
(a) 1 and 2
(b) 2 and 3
(c) 1 and 3
(d) 3 and 4
Answer : (d) Touch me not – living thing
Sunflower – living thing Water and cloud are nonliving things.
(3) and (4) shows movement in living things

5. Given below is the list of name of plants. Categorized as per their roots. Which one of the given categories is correct?
(a) Tap root: Wheat, mustard. Fibrous root: Onion, hibiscus
(b) Tap root: Onion, mustard. Fibrous root: Wheat, hibiscus
(c) Tap root: Hibiscus, mustard. Fibrous root: Onion, wheat
(d) All of these
Answer : (c) Taproot is the most central nd most dominant root from which other roots sprout laterally. e.g. beetroot, turnip etc. Fibrous root: It is opposite of tap root and is formed by thin moderately branching roots growing from the stem.

6. Ice changes into water and water changes into water vapour. What doyou conclude from this statement?
(a) Water is everywhere
(b) Water is a liquid
(c) Water is a gas
(d) Water is found in all the three states of matter
Answer : (d) Water - liquid form, water
vapour - gas form, ice - solid
form. From the given
statement we can conclude that water is found in all the three states of matter

7. Given below the list of things that happen during different seasons:
1. You sweat a lot.
2. You need warm clothes.
3. Plants shed their leaves.
4. There are flowers everywhere.
5. It rains heavily.
Which one of the following options is correct?
(a) 1-summer, 2-winter, 3-spring, 4-autumn, 5-rain
(b) 1-summer, 2-winter, 3-spring, 4-rain, 5-autumn
(c) 1-summer, 2-winter, 3-autumn, 4-spring, 5-rain
(d) 1-summer, 2-spring, 3-winter, 4-autumn, 5-rain
Answer : (c) In summer – you sweat a lot
In winters – you need warm clothes
In Autumn – plants shed their leaves
In Spring – there are flowers everywhere In Rain – it rains heavily.

8. Which statement is true?
Statement A : Sense organs help in obtaining information about the surroundings.
Statement B : Sense organs do not help in obtaining information about the surroundings..
(a) Statement A is true
(b) Statement B is true
(c) Both statement A and B are true
(d) Both statement A and B are false
Answer : (a) Sense organs ears, nose, eyes and skin help in obtaining information about the surroundings.

9. We eat the root of some plants that store food in them. Which one of the following plant’s root do we eat?
(a) Tomato
(b) Sugarcane
(c) Turnip
(d) Brinjal
Answer : (c) Turnip plant store food in the root.

10. What impact does the exhaled air make on lungs?
(a) Makes the lung expand
(b) Makes the lung contract
(c) Does not make any impact
(d) All of these
Answer : (b) When you exhale, air moves out from the body, this reduces space in the chest and makes the lung contract. When we inhale lungs expand.

11. Which one of the following process is responsible for the changing of water into water vapor?
(a) Condensation
(b) Freezing
(c) Evaporation
(d) All of these
Answer : (c) Water is liquid state and water vapour is gaseous state.
Evaporation is the process for conversion of a substance (water etc) from a liquid state to a gaseous state.

12. A student takes a balloon and fills it with air. What will he notice?
(a) He will notice that the mass of the balloon remains same
(b) He will notice that the mass of the balloon is increased
(c) He will notice that the mass of the balloon is decreased
(d) He will notice that the mass of the balloon is decreased by of the initial mass of the balloon
Answer : (b) Mass: amount of matter in an object; Air is a matter. When you take a balloon and fills it with air, you will notice that the mass of the balloon is increased.

13. A car travels 30 km in first hour, 31 km in second hour and again 30 km in third hour. What kind of motion does the car have?
(a) Uniform motion
(b) Non uniform motion
(c) Circular motion
(d) All of these
Answer : (b) Uniform motion: A car is said to have uniform motion if it travels equal distance in equal interval of time. eg

14. Which one of the following birds has chisel shaped beak?
(a) Woodpecker
(b) Parrot
(c) Crow
(d) Eagle
Answer : (a) Woodpecker has chisel shaped beak
Crow have sharp pointed triangle shaped beak. Parrot has stout red coloured beak.

15. The rocks are changed into soil by which one of the following process?
(a) Melting
(b) Soil erosion
(c) Chemical reaction
(d) Weathering
Answer : (d) Weathering is the breaking down of rocks, by physical and chemical process into soil.

16. Which one of the following is called the decomposer?
(a) Polyethylene
(b) Microorganism
(c) Minerals
(d) All of these
Answer : (b) Decomposer is a micro organism that cause organic material (plant or animal) to break down.

17. How can we prevent the depletion of ozone layer?
(a) By industrialization
(b) By deforestation
(c) By preventing pollution
(d) All of these
Answer : (c) Industrialization, deforestation are causes of pollution and pollution causes depletion of ozone layer. Thus, by preventing pollution we can prevent depletion of ozone layer.

18. We are able to see the moon because it .........................

(a) Gives out light
(b) is a glowing star
(c) reflects light from the sun
(d) reflects light from the earth
Answer : (c) We are able to see the moon because it reflects light from the sun.

19. Which statement is true?
Statement A : Population is a boon
Statement B : Over population is a bane.
(a) Statement A is true
(b) Statement B is true
(c) Both statement A and B are true
(d) Both statement A and B are false
Answer : (c) Population is a boon because we cannot do everything on our own but over population is a bane because there will be shortage of food and other resources

20. Which of the following birds can fly?
(a) Parrot
(b) Ostrich
(c) Kiwi
(d) All of these
Answer : (a) Parrot, Kiwi and Ostrich are all birds but all birds can’t fly, only parrot can fly.

21. Which of the following statement is correct?
(a) Plants require air, water and sunlight to make food.
(b) Man required food, air and water to live.
(c) Man requires only air to live.
(d) Both (a) and (b).
(d) Plants are living organisms, they require air, water, food and sunlight to live and make their food.

Answer : 22. The seed needs ________, ________ and ________ to grow.
(a) Water, air, warmth and sunshine
(b) Water, warmth and good soil
(c) Water, air and warmth
(d) Water, air and sunshine
Answer : (b) Seeds do not germinate until three needs are met : water, correct temperature (warmth) and good soil.

23. Which of the following statements are true about birds?
(a) They have hollow bones
(b) They have solid bones
(c) They have strong chest muscles
(d) Both (a) and (c)
Answer : (d) Birds have hollow, lightweight bones and have strong chest muscles to pull their wings up and down.

24. Which of the following organ helps us to make decisions?
(a) Eyes
(b) Ears
(c) Brain
(d) Nerves
Answer : (c) Our sense organs send signals to our brain and then helps us to act accordingly. So our brain help us to make decisions.

25. Which muscles are the busiest in the human body?
(a) Cheek muscles
(b) Eye muscles
(c) Hand muscles
(d) Leg muscles
Answer : (b) Eye muscles

26. Which part of the Earth is the coolest?
(a) Crust
(b) Core
(c) Mantle
(d) All of these
Answer : (a) Crust is the outer most part of the earth and is the coolest part.

27. Which of the following is the hardest rock?
(a) Coal
(b) Chalk
(c) Slate
(d) Diamond
Answer : (d) Diamond is the hardest rock among coal, chalk and slate, they are soft as compared to diamond.

28. In which of the following form fresh water is available?
(a) In the form of ice in glaciers
(b) As groundwater
(c) As water vapour in atmosphere
(d) All of these
Answer : (d) Water in the form of ice in glaciers, groundwater and water vapour in atmosphere are available in the form of fresh water.

29. Which of the following animals does not live on the land?

(d) All of these live on land
Answer : (d) Giraffe, cat and zebra all live on land

30. Which of the following is a correct food chain?
(a) Plants ® Deer ® Tiger
(b) Plants ® Eagle ® Tiger
(c) Wheat ® Eagle ® Tiger
(d) Plants ® Tiger ® Deer
Answer : (a) Plant is eaten by deer. Dear is eaten by tiger

31. Which of the following statement is true?
Statement A : Seeds grow into plants
Statement B : Buds grow into flowers.
(a) Statement A is correct
(b) Statement B is correct
(c) Statement A and B both are correct
(d) Neither statement A nor statement B is correct
Answer : (c) Both the statements are true.
Seeds grow into plants and buds grow into flowers.

32. Which of the following statement is true?
Statement A : The food made by the leaves travels through the stem to all parts of the plant.
Statement B : The food made by the leaves is always stored in stem.
(a) Statement A is correct
(b) Statement B is correct
(c) Statement A and B both are correct
(d) Neither statement A nor statement B is correct
Answer : (a) The food made by the leaves travel through the stem to all parts of the plant.
The food made by the leaves is stored in leaves only.

33. Identify our body system by which the waste material is removed from the body.
(a) Circulatory system
(b) Nervous system
(c) Skeletal system
(d) Excretory system
Answer : (d) Excretory system removes the waste material from the body.

34. Match the following :
1. Vulture (A) Has red coloured beak
2. Woodpecker (B) Has long and sharp beak
3. Kingfishers (C) Has strong and sharp beak
4. Parrot (D) Has long and scissors-like beak
(a) 1-C, 2-B, 3-D, 4-A
(b) 1-A, 2-C, 3-D, 4-B
(c) 1-D, 2-B, 3-A, 4-C
(d) 1-D, 2-C, 3-A, 4-B
(a) vultures – strong & sharp beak 
woodpecker – long and sharp beak
king fisher – long and scissors like beak
Answer : parrot – red coloured beak

35. Four students have made statements about the skeletal system.
Who all the correct? (Please choose all correct options)

(a) Jill and Jane
(b) Jack and Jill
(c) Jane and Jack
(d) Larry and Jill
Answer : (a) Jill and Jane