CBSE Class 3 Science ISO Olympiad MCQs with Answers Set 03

1. Which one of the following is the locomotory organ of a bird?
(a) Wings
(b) Legs
(c) Beak
(d) All of these
Answer : (a) Birds have wings to fly.

2. Which one of the following is called parasite?
(a) Lion
(b) Protozoa
(c) Calf
(d) All of these
Answer : (b) Protozoa are parasites because they live in the body of other organisms.

3. Which one of the following types of the microorganism is given in the picture below?

(a) Protozoa
(b) Plants
(c) Bacteria
(d) None of these
Answer : (c) The figure shows bacteria.

4. Consider the following statements :
Statement A : Some bacteria are harmful whereas some are useful for the human being.
Statement B : All bacteria are harmful for human being.
Which one of the following is correct about the above statements?
(a) Both statements are false
(b) Statement 1 is false and 2 is true
(c) Both statements are true
(d) Statement 1 is true and 2 is false
Answer : (d) Some bacteria are useful for human beings.

5. Which one of the following is responsible for the curd formation?
(a) Virus
(b) Bacteria
(c) Protozoa
(d) All of these
Answer : (b) Milk is converted into curd due to a bacteria.

6. Which one of the following medicines kills bacteria in our body?
(a) Vitamins oral suspension
(b) Digestive liquid
(c) Acidity remover
(d) Antibacterial medicine
Answer : (d) Antibacterial antibiotic kills bacteria in our body.

7. Which one of the following process involves the exchange of carbon dioxide and oxygen in the cells?
(a) Circulatory
(b) Respiration
(c) Excretion
(d) All of these
Answer : (b) Exchange of gases takes place through the process of respiration.

8. Which one of the following area is the most suitable for the human being?
(a) Plain
(b) Desert
(c) Hilly
(d) All of these
Answer : (a) Plains are most suitable for human beings.

9. Which one of the following is correct about the desert area?
(a) Less rain fall
(b) Favorable area for the growth
of the trees
(c) Fertile soil
(d) All of these
Answer : (a) Desert area has less rainfall.

10. The area near the mountain is called :
(a) Desert area
(b) Hilly area
(c) Plains
(d) All of these
Answer : (b) The area near the mountain is called hilly area.

11. How does the rabbit eat plants and plant part?
(a) Swallowing
(b) Chewing the cud
(c) Gnawing
(d) All of these
Answer : (c) Rabbit eats plants & plant parts by gnawing.

12. A plant is an example of a producer. Producers are living organisms that:
(a) make their own food
(b) break down dead organisms for food eat other organisms for food
(c) eat other organisms for food
(d) do not make their own food
Answer : (a) Producers are the organisms that make their own food.

13. Look at the following picture ofmolecular structure of a solid.
Which one of the following is correct about the solid?

(a) Molecules in solid are tightly packed
(b) Molecules in solid are loosely packed
(c) Molecules in solid move freely
(d) All of these
Answer : (a) In solid, the molecules are tightly packed

14. What is measured in liquid form of a substance?
(a) Length
(b) Width
(c) Volume
(d) Height
Answer : (c) In a liquid form of a substance, volume is measured.

15. Two substances, sodium and chlorine are mixed to form sodium chloride. This is an example of which one of the following?
(a) Physical change
(b) Both physical and chemical change
(c) Chemical reaction
(d) Partially physical and chemical change
Answer : (c) Sodium reacts with chlorine to form sodium chloride. This is a chemical reaction.

16. Oxygen and digested food in our body react to form which one of the following?
(a) Energy
(b) Vitamins
(c) Minerals
(d) All of these
Answer : (a) The digested food is oxidised to form energy.

17. A man applies a force for the displacement of the solid. If solid does not move from one place to another, what will be the conclusion?
(a) Work has been done
(b) No work has been done
(c) No force on the solid
(d) All of these
Answer : (b) No displacement means no work done.

18. A force which is naturally applied to everything on the earth is called :
(a) Force of gravity
(b) Frictional force
(c) Tension
(d) All of these
Answer : (a) Force of gravity is the force naturally applied to everything on the earth.

19. Which one of the following will fall fast on the ground if they are dropped from an equal height?
A plastic ball An iron ball
(a) Plastic ball
(b) Iron ball
(c) Both will take equal time
(d) All of these
Answer : (b) The iron ball will fall first because it is heavier than plastic ball.

20. Which one of the following types of force will work between a magnet and a piece of iron?
(a) Frictional force
(b) Gravitational force
(c) Magnetic force
(d) All of these
Answer : (c) The force between a magnet and a piece of iron is called magnetic force.

21. Grass appears green because:
(a) It absorbs green light.
(b) It reflects green light back to your eyes.
(c) It reflects red light back to your eyes.
(d) It reflects white light.
Answer : (a) Grass reflects green light back to your eyes.

22. Which one of the following types of force is there between the moving object A and B ?
A →
← B
(a) Gravitational force
(b) There is no force between A and B
(c) Frictional force
(d) All of these
Answer : (c) The moving object A and B will experience frictional force.

23. Experiment : Light a torch on a wall and put a ball between the torch and the wall. What will you observe?
(a) A shadow of ball on the wall
(b) A shadow of torch on the wall
(c) A shadow of wall on the ball
(d) All of these
Answer : (a) When a ball is placed between a torch & a wall, the shadow of ball can be seen on the wall.

24. Arrange the following in increasing order according to their capacity :
Bottle, Glass, Tub, Tank
(a) Tank, Tub, Bottle, Glass
(b) Glass, Bottle, Tub, Tank
(c) Tub, Tank, Bottle, Glass
(d) Bottle, Tank, Glass, Tub
Answer : (b) Glass is the smallest, then bottle followed by tub and tank has the highest capacity.

25. Consider the following statements :
Statement 1 : Circulatory system consists of the heart and blood vessels.
Statement 2 : The blood vessels carry blood from the heart to different parts of the body.
Which one of the following is correct about the above statements?
(a) Statement 1 is true and 2 is false
(b) Statement 1 is false and 2 is true
(c) Both statements are false
(d) Both statements are true
Answer : (d) Both the statements are true.

26. Recycling refers to:
(a) burning trash completely
(b) burying trash in a landfill
(c) reducing the amount of waste left over from using a product
(d) reusing a resource to make something new.
Answer : (d) Recycling means reusing a resource to make something new.

27. What is the name of the process by which a seed grows into a baby plant?
(a) Germination
(b) Gardening
(c) Graduated
(d) All of these
Answer : (a) A seed germinates to give rise to a baby plant.

28. A few substances change directly from solid into gas on heating.
Which one of the following process involves for the same?
(a) Sublimation
(b) Freezing
(c) Sub-cancellation
(d) All of these
Answer : (a) Sublimation is the process of changing solid directly into gas.

29. A substance is capable of passing electric current through itself.
What is the substance called?
(a) Conductor
(b) Bad conductor
(c) Insulator
(d) All of these
Answer : (a) Conductor is the substance that can pass electric current through itself.

30. A substance has property not just like the property of metal and non metal. It has some property of
metal and some of non metal. What is the substance called?
(a) Non metal
(b) Metal
(c) Metalloids
(d) All of these
Answer : (c) Metalloids have properties of both metals and non-metals

31. Individual cells in our body combine to form a tissue. What is formed by the combination of individual bone?
(a) Skeletal system
(b) Organs
(c) Muscular system
(d) All of these
Answer : (a) Individual bones combine together to form skeletal system.

32. Which one of the following lays eggs instead of giving birth to young one?

Answer : (a) Birds lay eggs, rest are mammals giving birth to young ones.

33. A mineral is a natural crystalline solid formed from geological processes. Which is not an example of a mineral?
(a) Diamond
(b) wood
(c) Gold
(d) Salt
Answer : (b) Wood is not a mineral.

34. Which one of the following can control the possibility of heart attack?
(a) Hard exercise
(b) Low fat diet
(c) High fat diet
(d) All of these
Answer : (b) Low fat diet can control the possibility of heart attack.

35. Which one of the following is not a pet animal?
(a) Cat
(b) Dog
(c) Rabbit
(d) Tiger
Answer : (d) Tiger cannot be tamed.