NCERT Class 8 Science MCQ | Chapter 13: Our Home: Earth, a Unique Life Sustaining Planet
1. What makes Earth unique among the planets known to us?
(A) It is the largest planet
(B) It is the only known planet where life exists and thrives
(C) It is the closest planet to the Sun
(D) It has no atmosphere
Answer: (B) It is the only known planet where life exists and thrives
2. Which layer of Earth is described as the thin, life-supporting layer?
(A) Inner core
(B) Outer core
(C) Crust
(D) Lower mantle
Answer: (C) Crust
3. Which of the following is one of the important resources provided by Earth?
(A) Air
(B) Water
(C) Soil
(D) All of the above
Answer: (D) All of the above
4. How many planets are there in our solar system?
(A) Six
(B) Seven
(C) Eight
(D) Nine
Answer: (C) Eight
5. Which of the following is a rocky planet?
(A) Jupiter
(B) Saturn
(C) Earth
(D) Neptune
Answer: (C) Earth
6. Why is Venus the hottest planet in the solar system?
(A) It is the closest planet to the Sun
(B) It has a thick atmosphere that traps heat
(C) It receives no sunlight
(D) It has no atmosphere
Answer: (B) It has a thick atmosphere that traps heat
7. Which gas makes up most of the atmosphere of Venus?
(A) Oxygen
(B) Nitrogen
(C) Carbon dioxide
(D) Hydrogen
Answer: (C) Carbon dioxide
8. What is the greenhouse effect?
(A) The cooling of Earth by clouds
(B) The trapping of heat by certain gases in the atmosphere
(C) The movement of Earth around the Sun
(D) The reflection of sunlight by the Moon
Answer: (B) The trapping of heat by certain gases in the atmosphere
9. Why is Earth’s distance from the Sun important for life?
(A) It allows water to exist mainly in liquid form
(B) It prevents Earth from rotating
(C) It removes the atmosphere
(D) It makes Earth the largest planet
Answer: (A) It allows water to exist mainly in liquid form
10. What is the habitable zone?
(A) The region where no water can exist
(B) The range of distances from a star where water can remain liquid
(C) The region occupied only by gas giants
(D) The region beyond all planets
Answer: (B) The range of distances from a star where water can remain liquid
11. The habitable zone is also called the:
(A) Ozone zone
(B) Goldilocks zone
(C) Magnetic zone
(D) Solar zone
Answer: (B) Goldilocks zone
12. Why is Earth called the Blue Planet?
(A) Its atmosphere is blue
(B) It has a large amount of water on its surface
(C) Its soil is blue
(D) It receives blue light from the Sun
Answer: (B) It has a large amount of water on its surface
13. Why is Earth’s size important for supporting life?
(A) It gives Earth enough gravity to retain its atmosphere
(B) It prevents Earth from receiving sunlight
(C) It makes Earth the closest planet to the Sun
(D) It removes all gases from the atmosphere
Answer: (A) It gives Earth enough gravity to retain its atmosphere
14. What would happen if Earth were much smaller, with the same average density?
(A) Its gravity would become too weak to retain the atmosphere effectively
(B) Its gravity would become extremely strong
(C) Its oceans would disappear immediately
(D) Its atmosphere would become thicker
Answer: (A) Its gravity would become too weak to retain the atmosphere effectively
15. What is the main function of the ozone layer?
(A) It produces oxygen
(B) It blocks harmful ultraviolet rays from the Sun
(C) It produces rainfall
(D) It increases Earth’s gravity
Answer: (B) It blocks harmful ultraviolet rays from the Sun
16. What acts as a protective shield against many high-energy particles coming from space?
(A) Earth’s oceans
(B) Earth’s magnetic field
(C) Earth’s soil
(D) Earth’s forests
Answer: (B) Earth’s magnetic field
17. What is believed to be the origin of Earth’s magnetic field?
(A) Movement of molten iron in Earth’s core
(B) Movement of ocean water
(C) Rotation of the Moon
(D) Clouds in the atmosphere
Answer: (A) Movement of molten iron in Earth’s core
18. Which of the following correctly describes the hydrosphere?
(A) The solid part of Earth
(B) All the water found on Earth
(C) All living organisms on Earth
(D) The layer of gases around Earth
Answer: (B) All the water found on Earth
19. Which of the following is known as the geosphere?
(A) The solid parts of Earth, including rocks, soil, and minerals
(B) All living organisms
(C) All water bodies
(D) The atmosphere only
Answer: (A) The solid parts of Earth, including rocks, soil, and minerals
20. What is the biosphere?
(A) The layer containing only rocks
(B) All living beings along with the places where they live
(C) The layer containing only water
(D) The outermost layer of the atmosphere
Answer: (B) All living beings along with the places where they live
21. What is geodiversity?
(A) Variety of living organisms
(B) Variety of landforms, rocks, soils, and the processes that shape them
(C) Variety of gases in the atmosphere
(D) Variety of planets in the solar system
Answer: (B) Variety of landforms, rocks, soils, and the processes that shape them
22. What is the main importance of reproduction for life on Earth?
(A) It stops variation
(B) It ensures the continuity of life
(C) It prevents organisms from adapting
(D) It reduces biodiversity
Answer: (B) It ensures the continuity of life
23. Which type of reproduction involves a single parent producing new individuals that are essentially copies of itself?
(A) Sexual reproduction
(B) Asexual reproduction
(C) Fertilisation
(D) Pollination
Answer: (B) Asexual reproduction
24. Which of the following is an example of vegetative propagation?
(A) A new plant growing from a potato eye
(B) A bird laying an egg
(C) Fertilisation in a flower
(D) A frog producing eggs
Answer: (A) A new plant growing from a potato eye
25. Which three environmental challenges are together called the “triple planetary crisis”?
(A) Soil erosion, earthquakes, and floods
(B) Climate change, biodiversity loss, and pollution
(C) Deforestation, earthquakes, and volcanic eruptions
(D) Drought, storms, and cyclones
Answer: (B) Climate change, biodiversity loss, and pollution
Class 8 Science Chapter 13: Our Home: Earth, a Unique Life Sustaining Planet
Assertion–Reason Questions
Directions: Choose the correct option:
(A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
(B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
(C) Assertion is true, but Reason is false.
(D) Assertion is false, but Reason is true.
1. Assertion: Earth is suitable for supporting life.
Reason: Earth is at a suitable distance from the Sun, allowing water to exist mainly in liquid form.
Answer: (A)
2. Assertion: Venus is hotter than Mercury.
Reason: Venus has a thick atmosphere containing a large amount of carbon dioxide that traps heat.
Answer: (A)
3. Assertion: The ozone layer is important for life on Earth.
Reason: The ozone layer helps block harmful ultraviolet radiation from the Sun.
Answer: (A)
4. Assertion: Earth’s magnetic field helps protect life on Earth.
Reason: It pushes many harmful high-energy particles coming from space away from Earth.
Answer: (A)
5. Assertion: Reproduction is essential for the continuity of life.
Reason: Reproduction allows organisms to produce new individuals and also allows variations to arise through sexual reproduction.
Answer: (A)
