Students can practice the best Class 8 Science MCQ and Our Home Earth A Unique Life Sustaining Planet Class 8 Science Curiosity Chapter 13 MCQ Online Test with Answers for exam preparation.
Class 8 Science Chapter 13 Our Home Earth A Unique Life Sustaining Planet MCQ
Our Home Earth A Unique Life Sustaining Planet MCQ
Class 8 Science Chapter 13 MCQ Online Test
Question 1.
Paheli read that Earth’s atmosphere remains around the planet, even though gases are free to move. Which factor ensures this?
(a) Moon’s gravity
(b) Solar energy
(c) Earth’s gravity
(d) Earth’s tilt
Answer:
(c) Earth’s gravity
Question 2.
A student left two jars, one with a plant and one without, both closed. After a day in sunlight, oxygen levels increased only in one. What does this demonstrate?
(a) Plants absorb oxygen
(b) Plants release heat
(c) Plants help make oxygen
(d) Plants block sunlight
Answer:
(c) Plants help make oxygen
Question 3.
A village noticed fewer fish in rivers due to deforestation nearby. What interaction of Earth’s systems does this show?
(a) Air quality affecting climate
(b) Geosphere affecting atmosphere
(c) Biosphere affecting lithosphere
(d) Land changes affecting water life
Answer:
(d) Land changes affecting water life
Question 4.
Which is an indirect way Earth’s magnetic field supports life?
(a) Keeps ocean currents steady
(b) Helps birds fly
(c) Blocks solar radiation
(d) Makes gravity stronger
Answer:
(c) Blocks solar radiation
Question 5.
Venus is hotter than Mercury. A student said this was strange since Mercury is closer to the Sun. The reason is
(a) mercury has too many craters
(b) venus has a thick CO2 atmosphere
(c) mercury spins faster
(d) venus has more volcanoes
Answer:
(b) venus has a thick CO2 atmosphere
Question 6.
A classroom discussion was about the Earth’s spheres. Which example shows interaction between geosphere and biosphere?
(a) Air mixing with clouds
(b) River water flowing to sea
(c) Tree roots breaking rocks
(d) Ocean tides changing
Answer:
(c) Tree roots breaking rocks
Question 7.
On which planet is it difficult to walk or survive because it has no thick atmosphere or air pressure like Earth?
(a) Mars
(b) Neptune
(c) Jupiter
(d) Venus
Answer:
(a) Mars
Question 8.
In sexual reproduction, which of the following ensures that the offspring does not have double the amount Of genetic material? (Competency Based Que.)
(a) Fertilisation
(b) Formation of gametes
(c) Pollination
(d) Zygote division
Answer:
(b) Formation of gametes
Question 9.
Which of the following is NOT a pollinating agent?
(a) Wind
(b) Birds
(c) Insects
(d) Fungi
Answer:
(d) Fungi
Question 10.
In birds, the embryo develops
(a) outside the female body in a laid egg.
(b) inside the female body until it hatches.
(c) only after the zygote is fertilised by insects.
(d) in the male body.
Answer:
(a) outside the female body in a laid egg.
Question 11.
Which of these is a direct effect of burning fossil fuels?
(a) Decrease in carbon dioxide
(b) Melting of ice caps
(c) Increased pollination in plants
(d) Reduced biodiversity
Answer:
(b) Melting of ice caps
Question 12.
A scientist finds a planet with water but no magnetic field. Which challenge might life face there?
(a) Extreme cold
(b) Lack of oxygen
(c) No protection from harmful space particles
(d) Water turning into gas
Answer:
(c) No protection from harmful space particles
Question 13.
Which of the following explains why Earth doesn’t lose its atmosphere like the Moon?
(a) It spins faster
(b) It has more mountains
(c) Its size ensures enough gravity
(d) It has more clouds
Answer:
(c) Its size ensures enough gravity
Question 14.
If a flower’s ovule doesn’t develop after fertilisation, what is most likely to be affected?
(a) Formation of leaves
(b) Development of fruit
(c) Process of pollination
(d) Amount of sunlight it receives
Answer:
(b) Development of fruit
Question 15.
Mars is part of the habitable zone, yet no life is found. What might be missing?
(a) Enough gravity for tides
(b) A proper balance of oxygen and nitrogen
(c) Thick clouds for sunlight reflection
(d) Transparent atmosphere
Answer:
(b) A proper balance of oxygen and nitrogen
Question 16.
If Earth’s axis tilted more, what part of life could be most directly affected?
(a) Ocean currents
(b) Amount of sunlight received in regions
(c) Gravitational pull
(d) Ozone formation
Answer:
(b) Amount of sunlight received in regions
Our Home Earth A Unique Life Sustaining Planet Class 8 Assertion Reason Questions
The following questions consist of two statements.
Assertion (A) and Reason (R). Answer the following questions by selecting the appropriate option given below
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Question 1.
Assertion (A) Earth supports life because it is at the right distance from the Sun.
Reason (R) This distance allows water to stay in liquid form.
Answer:
(a) Both A and R are true and R is the correct explanation of A.
Question 2.
Assertion (A) Plants cannot grow in sealed jars without sunlight.
Reason (R) Sunlight is required for photosynthesis.
Answer:
(a) Both A and R are true and R is the correct explanation of A.
Question 3.
Assertion (A) Removing forests can reduce rainfall in an area.
Reason (R) Forests add moisture to the air and help in cloud formation.
Answer:
(a) Both A and R are true and R is the correct explanation of A.
Question 4.
Assertion (A) Gametes carry only half of the parent’s genetic material.
Reason (R) This ensures that when male and female gametes combine, the new cell has a complete set of genetic instructions.
Answer:
(a) Both A and R are true and R is the correct explanation of A.
Question 5.
Assertion (A) Earth’s magnetic field is invisible yet essential.
Reason (R) It helps bounce sound waves back to Earth.
Answer:
(c) A is true but R is false.
Question 6.
Assertion (A) Internal fertilisation in mammals provides better protection to offspring.
Reason (R) The embryo develops inside the body, receiving care and nutrients.
Answer:
(a) Both A and R are true and R is the correct explanation of A.
Question 7.
Assertion (A) The biosphere includes only land-dwelling animals and plants.
Reason (R) Aquatic life does not depend on sunlight or oxygen.
Answer:
(d) A is false but R is true.
Our Home Earth A Unique Life Sustaining Planet Class 8 Case Based MCQ Questions
Question 1.
Earth functions as a complex system where different spheres interact. The atmosphere provides air and climate, the hydrosphere includes all water bodies, the geosphere forms the land and rocks, and the biosphere contains ail life. When one sphere is disturbed, others are often affected. For example, deforestation (biosphere) can lead to soil erosion (geosphere) and reduced rainfall (atmosphere).
(i) The part of Earth that includes lakes and oceans is the
(a) atmosphere
(b) biosphere
(c) geosphere
(d) hydrosphere
Answer:
(d) hydrosphere
(ii) The system responsible for soil formation and rock breakdown is
(a) Biosphere
(b) Geosphere
(c) Atmosphere
(d) Hydrosphere
Answer:
(b) Geosphere
(iii) If animals die due to polluted air, which system was primarily disturbed?
(a) Hydrosphere
(b) Geosphere
(c) Atmosphere
(d) Biosphere
Answer:
(c) Atmosphere
(iv) The layer that protects us from UV rays and supports weather changes is
(a) biosphere
(b) hydrosphere
(c) geosphere
(d) atmosphere
Answer:
(d) atmosphere
Question 2.
While observing deep space images from a new satellite, scientists discovered a distant planet named Zora. It lies in the habitable zone of its star, similar in distance to Earth from the Sun. Interestingly, Zora has liquid water, an atmosphere rich in oxygen and evidence of photosynthetic activity. However, its magnetic field is extremely weak and large portions of its landmass are rapidly losing topsoil. Scientists also observed that Zora’s climate is warming due to an increase in greenhouse gases, especially carbon dioxide.
The planet has life in various forms, including plants, animals and microorganisms. However, recent signals show massive deforestation and plastic waste in its ocean-like bodies. The space agency is considering sending an awareness module with basic guidelines on maintaining life balance like Earth’s systems-biosphere, atmosphere, hydrosphere and geosphere.
(i) Despite having oxygen and water, what major factor threatens Zora’s ability to sustain life in the long term?
(a) Its lack of mountains
(b) Weak magnetic shielding
(c) Smaller size than Earth
(d) Slower rotation speed
Answer:
(b) Weak magnetic shielding
(ii) Which natural system is likely breaking down due to topsoil loss on Zora?
(a) Atmosphere
(b) Geosphere
(c) Biosphere
(d) Hydrosphere
Answer:
(b) Geosphere
(iii) What process is most likely happening due to high carbon dioxide levels on Zora?
(a) Deforestation
(b) Rapid plant growth
(c) Extreme greenhouse effect
(d) Decrease in oxygen production
Answer:
(c) Extreme greenhouse effect
(iv) Which relationship in Zora’s biosphere supports the idea of interdependence among living beings?
(a) Plastic accumulation in oceans
(b) Fusion of gametes in reproduction
(c) Microorganisms decomposing organic matter
(d) Rotation of Zora around its star
Answer:
(c) Microorganisms decomposing organic matter
Our Home Earth A Unique Life Sustaining Planet Class 8 Fill in the blanks
1. The natural system that includes all living organisms and the environments they interact with is the _____________ .
Answer:
Ecosystem
2. _____________ helps in returning nutrients to the soil after plants and animals die.
Answer:
Decomposers
3. The _____________ field of the Earth acts like a protective shield from harmful solar particles.
Answer:
Magnetic
4. The layer of gases around Earth that supports life is called the _____________ .
Answer:
Atomosphere
5. The process of transferring pollen from the anther to the stigma of a flower is called _____________ .
Answer:
Pollination
6. In humans, the male gamete is called _____________ and the female gamete is called _____________ .
Answer:
Sperm egg (ovum)
7. Long-term changes in temperature, rainfall and weather patterns due to human activity are referred to as _____________ .
Answer:
Climate change
Our Home Earth A Unique Life Sustaining Planet Class 8 True or False
1. The greenhouse effect on Earth works exactly like a plant greenhouse.
Answer:
False
2. Decomposers play a role in recycling nutrients.
Answer:
True
3. Venus is hotter than Mercury because of its distance from the Sun.
Answer:
False
4. Life on Earth depends only on the biosphere.
Answer:
False
5. Earth’s unique position in the solar system makes liquid water possible.
Answer:
True
6. Sexual reproduction always requires two different parents.
Answer:
False
7. Fertilisation in humans occurs outside the female body.
Answer:
False
8. Climate change can increase sea levels due to melting ice caps.
Answer:
True
9. Each baby inherits identical genetic instructions from both parents.
Answer:
False
10. Birds lay fertilised eggs where the zygote develops outside the female body.
Answer:
True
11. Venus traps more heat than Earth due to its thick carbon dioxide layer.
Answer:
True
12. All microorganisms are harmful to the biosphere.
Answer:
False
13. The balance of gases in nature is affected by both respiration and photosynthesis.
Answer:
True
Our Home Earth A Unique Life Sustaining Planet Class 8 Match the following
Question 1.
Match the Column I with Column II.
| Column I | Column II |
| A. Hydrosphere | 1. Oceans, lakes, rivers |
| B. Magnetic field | 2. Blocks harmful solar particles |
| C. Biosphere | 3. Living organisms |
| D. Decomposers | 4. Breaks down waste and dead material |
Answer:
| Column I | Column II |
| A. Hydrosphere | 1. Oceans, lakes, rivers |
| B. Magnetic field | 2. Blocks harmful solar particles |
| C. Biosphere | 3. Living organisms |
| D. Decomposers | 4. Breaks down waste and dead material |
A – 1, B – 2, C – 3, D – 4,
Question 2.
Match the Column I with Column II.
| Column I | Column II |
| A. Zygote | 1. Male reproductive cell |
| B. Pollination | 2. Combination gametes |
| C. Sperm | 3. Transfer of pollen |
| D. Ovule | 4. Female reproductive part |
Answer:
A – 2, B – 3, C – 1, D – 4
| Column I | Column II |
| A. Zygote | 2. Combination gametes |
| B. Pollination | 3. Transfer of pollen |
| C. Sperm | 1. Male reproductive cell |
| D. Ovule | 4. Female reproductive part |