Looking for the most important Class 8 Science Chapter 13 MCQs for quick revision? You're in the right place. This page brings together carefully selected multiple-choice questions from Our Home: Earth, a Unique Life Sustaining Planet to help students prepare effectively for school exams. Whether you're revising after completing the chapter or practising just before an assessment, these MCQs are designed to strengthen your understanding of key concepts while improving your accuracy in objective questions.
Each question is followed by the correct answer and a simple explanation, allowing you to learn from every attempt instead of just checking the right option. The practice set follows the latest CBSE Board syllabus and NCERT guidelines, making it suitable for unit tests, periodic tests, half-yearly, and annual examinations.
If you're preparing chapter by chapter, don't forget to explore our complete collection of Class 8 MCQs for all subjects. You can also practise more Class 8 Science MCQs to build a stronger conceptual foundation and boost your exam confidence through regular revision.
Class 8 Science Chapter 13 MCQs with Answers & Explanations
The questions below are organised according to different cognitive levels to support step-by-step learning and effective exam preparation.
Section A: Remembering MCQs
This section focuses on fundamental facts, definitions, and concepts from the chapter. These questions help you recall important information directly from the NCERT textbook and build a strong conceptual foundation.
Q. Which planet in our solar system is known to support life?
A. Mars
B. Venus
C. Earth
D. Mercury
Answer: C
Explanation:
Earth is the only known planet that naturally supports life because it has liquid water, a protective atmosphere, suitable temperatures, and essential gases like oxygen. These conditions work together to create an environment where plants, animals, and humans can survive and thrive.
Q. Which layer of the Earth contains all living organisms?
A. Atmosphere
B. Lithosphere
C. Hydrosphere
D. Biosphere
Answer: D
Explanation:
The biosphere is the zone where life exists on Earth. It includes parts of the land, water, and air that support living organisms. Since all plants, animals, and microorganisms live within this region, it plays a vital role in maintaining Earth's ecological balance.
Q. What is the atmosphere mainly composed of?
A. Water and soil
B. Air surrounding the Earth
C. Rocks and minerals
D. Molten lava
Answer: B
Explanation:
The atmosphere is the blanket of air surrounding Earth. It contains gases such as nitrogen, oxygen, carbon dioxide, and water vapour. Besides supporting life, it also protects Earth from harmful radiation and helps regulate the planet's temperature.
Q. Which sphere of the Earth includes oceans, rivers, lakes, and groundwater?
A. Biosphere
B. Lithosphere
C. Hydrosphere
D. Atmosphere
Answer: C
Explanation:
The hydrosphere includes all forms of water present on Earth, including oceans, rivers, lakes, glaciers, groundwater, and water vapour. Water is essential for every living organism, making the hydrosphere one of the most important components of our planet.
Q. The solid outer part of the Earth is called the:
A. Atmosphere
B. Hydrosphere
C. Lithosphere
D. Biosphere
Answer: C
Explanation:
The lithosphere is Earth's solid outer layer made up of rocks, soil, and minerals. It provides land for forests, agriculture, industries, and human settlements. It also supplies valuable natural resources that support everyday life and economic activities.
Q. Which gas is most abundant in Earth's atmosphere?
A. Oxygen
B. Nitrogen
C. Carbon dioxide
D. Hydrogen
Answer: B
Explanation:
Nitrogen forms about 78% of Earth's atmosphere, making it the most abundant gas. Although humans mainly depend on oxygen for respiration, nitrogen plays an essential role in maintaining atmospheric stability and supporting the nitrogen cycle in nature.
Q. Which natural resource is essential for photosynthesis in green plants?
A. Coal
B. Petroleum
C. Carbon dioxide
D. Natural gas
Answer: C
Explanation:
Green plants absorb carbon dioxide from the atmosphere during photosynthesis. Using sunlight and water, they produce food and release oxygen. This process not only supports plant growth but also maintains the balance of gases necessary for life on Earth.
Q. Which of the following is a renewable natural resource?
A. Coal
B. Petroleum
C. Wind
D. Natural gas
Answer: C
Explanation:
Wind is considered a renewable resource because it is naturally replenished and does not get exhausted through regular use. Unlike fossil fuels such as coal and petroleum, wind energy provides a cleaner and more sustainable source of power.
Q. Which of the following is NOT a component of the biosphere?
A. Plants
B. Animals
C. Microorganisms
D. Molten magma deep inside Earth
Answer: D
Explanation:
The biosphere includes all living organisms and the regions where they exist. Molten magma is found deep inside Earth's interior and does not support life. Therefore, it is not considered a part of the biosphere.
Q. Why is Earth often called a unique life-sustaining planet?
A. It is the largest planet.
B. It has the highest mountains.
C. It provides suitable conditions for life.
D. It is closest to the Sun.
Answer: C
Explanation:
Earth is unique because it has the right combination of air, water, suitable temperature, fertile land, and a protective atmosphere. These conditions create an environment where diverse forms of life can survive, grow, and reproduce, making Earth different from other known planets.
Section B: Understanding MCQs
These questions test whether you truly understand the concepts rather than simply remembering facts. They encourage you to connect ideas, identify relationships, and explain why Earth is capable of supporting life.
Q. Why is the atmosphere important for sustaining life on Earth?
A. It increases the Earth's weight.
B. It provides essential gases and protects Earth from harmful radiation.
C. It produces minerals for industries.
D. It creates mountains and valleys.
Answer: B
Explanation:
The atmosphere does much more than surround Earth with air. It supplies oxygen for respiration, carbon dioxide for photosynthesis, and acts as a protective shield against harmful ultraviolet rays and many meteoroids. It also helps maintain a stable temperature, making life possible.
Q. Which statement best explains why liquid water is essential for life?
A. It changes the colour of rocks.
B. It helps planets rotate faster.
C. It supports biological processes in all living organisms.
D. It increases the amount of oxygen in space.
Answer: C
Explanation:
Water is involved in almost every life process, including digestion, transportation of nutrients, photosynthesis, and temperature regulation. Since all known living organisms depend on water to survive, its presence is one of the main reasons Earth can sustain life.
Q. The biosphere depends on the atmosphere, hydrosphere, and lithosphere because:
A. Living organisms interact with air, water, and land.
B. They are located at the Earth's core.
C. They move around the Sun together.
D. They contain only non-living materials.
Answer: A
Explanation:
Life exists because living organisms continuously interact with land, water, and air. Plants grow in soil, animals require water, and all organisms depend on atmospheric gases. Together, these spheres create interconnected ecosystems that support life on Earth.
Q. Which activity best helps conserve natural resources?
A. Cutting forests without replanting trees.
B. Wasting water during daily activities.
C. Using resources wisely and reducing unnecessary consumption.
D. Burning more fossil fuels every day.
Answer: C
Explanation:
Conservation means using natural resources responsibly so they remain available for future generations. Simple practices such as saving water, planting trees, recycling materials, and reducing pollution help protect Earth's environment and maintain ecological balance.
Q. Why is biodiversity important for the environment?
A. It reduces the number of ecosystems.
B. It increases pollution levels.
C. It helps maintain stable and healthy ecosystems.
D. It prevents rainfall completely.
Answer: C
Explanation:
Biodiversity refers to the variety of living organisms on Earth. Different species perform different ecological roles, such as pollination, nutrient cycling, and food chain maintenance. A rich biodiversity makes ecosystems more stable, productive, and capable of adapting to environmental changes.
Q. Which of the following would most likely disturb ecological balance?
A. Afforestation
B. Rainwater harvesting
C. Large-scale deforestation
D. Recycling waste materials
Answer: C
Explanation:
Deforestation destroys habitats, reduces biodiversity, and disrupts food chains. It also affects rainfall patterns, increases soil erosion, and contributes to climate change. Protecting forests is essential for maintaining ecological balance and supporting countless forms of life.
Q. Earth remains suitable for life mainly because its different spheres:
A. Function independently without affecting one another.
B. Continuously interact to support living organisms.
C. Exist only during the rainy season.
D. Contain only renewable resources.
Answer: B
Explanation:
The atmosphere, hydrosphere, lithosphere, and biosphere constantly interact with one another. Water cycles through air and land, plants exchange gases with the atmosphere, and soil supports vegetation. These interactions create conditions that allow life to flourish on Earth.
Q. What is the most likely result of excessive pollution of rivers and lakes?
A. Increased biodiversity in aquatic ecosystems.
B. Improved quality of drinking water.
C. Harm to aquatic life and reduced availability of clean water.
D. Faster formation of mountains.
Answer: C
Explanation:
Water pollution introduces harmful substances into rivers and lakes, affecting fish, plants, and other aquatic organisms. It also reduces the availability of safe drinking water for humans and animals, highlighting the importance of protecting freshwater resources.
Q. Why are fossil fuels considered non-renewable resources?
A. They can be produced within a few days.
B. They are formed over millions of years and cannot be replaced quickly.
C. They are available in unlimited quantities.
D. They are found only in oceans.
Answer: B
Explanation:
Coal, petroleum, and natural gas take millions of years to form from the remains of ancient organisms. Since humans consume these resources much faster than nature can replace them, they are classified as non-renewable and should be used carefully.
Q. Which statement correctly describes the relationship between humans and the environment?
A. Humans are completely independent of nature.
B. Humans depend on natural resources for survival and should protect them.
C. Natural resources have no role in human life.
D. Environmental conservation is important only for wild animals.
Answer: B
Explanation:
Humans rely on the environment for air, water, food, energy, and raw materials. Unsustainable use of these resources can harm ecosystems and reduce their availability. Conserving the environment ensures that both present and future generations can meet their needs responsibly.
Section C: Application-Based MCQs
Application-based questions help you use scientific concepts in real-life situations. They reflect the competency-based approach adopted by CBSE and prepare you for higher-order thinking questions in school examinations.
Q. A village starts collecting rainwater in storage tanks during the monsoon. Which objective is best achieved through this practice?
A. Increasing air pollution
B. Conserving water resources
C. Reducing soil fertility
D. Increasing the use of fossil fuels
Answer: B
Explanation:
Rainwater harvesting helps store water that can be used during dry seasons, reducing dependence on groundwater. It is an effective method of conserving freshwater resources and supports sustainable water management, especially in areas facing water scarcity.
Q. A factory releases untreated waste into a nearby river. Which part of the Earth is directly affected first?
A. Atmosphere
B. Lithosphere
C. Hydrosphere
D. Biosphere
Answer: C
Explanation:
Since the waste is discharged into a river, the hydrosphere is affected first. Polluted water can later harm aquatic organisms, contaminate drinking water, and indirectly impact the biosphere, showing how Earth's different spheres are closely interconnected.
Q. A community plants thousands of trees in a barren area. What is the most likely long-term benefit?
A. Increased soil erosion
B. Improved biodiversity and ecological balance
C. Decreased oxygen levels
D. Faster depletion of natural resources
Answer: B
Explanation:
Tree plantation creates habitats for many organisms, improves soil quality, and increases oxygen production. Over time, it supports biodiversity and helps restore ecological balance, making the environment healthier for both wildlife and humans.
Q. A family replaces ordinary bulbs with LED lights and switches off electrical appliances when not in use. This practice mainly promotes:
A. Wastage of natural resources
B. Conservation of energy resources
C. Increase in greenhouse gas emissions
D. Depletion of renewable resources
Answer: B
Explanation:
Using energy-efficient appliances and avoiding unnecessary electricity consumption reduces the demand for power generation. Since much of the world's electricity is still produced from fossil fuels, saving energy helps conserve natural resources and lowers environmental pollution.
Q. Farmers begin using organic manure instead of excessive chemical fertilizers. Which outcome is most likely?
A. Improved soil health and reduced pollution
B. Complete loss of soil nutrients
C. Increased water pollution only
D. Faster depletion of groundwater
Answer: A
Explanation:
Organic manure improves soil structure, increases fertility, and supports beneficial microorganisms. Compared to excessive chemical fertilizers, it reduces soil and water pollution while promoting sustainable agricultural practices that protect the environment.
Q. A city develops more parks and protects existing green spaces. Which environmental benefit is most likely?
A. Decrease in oxygen production
B. Better air quality and improved living conditions
C. Higher levels of water pollution
D. Reduction in biodiversity
Answer: B
Explanation:
Parks and green spaces improve air quality by absorbing carbon dioxide and releasing oxygen. They also provide habitats for birds and insects, reduce urban heat, and create a healthier environment, demonstrating the importance of conserving natural vegetation.
Q. During a camping trip, students are advised to carry reusable water bottles instead of disposable plastic bottles. What is the main purpose of this advice?
A. To increase plastic waste
B. To conserve resources and reduce pollution
C. To consume more groundwater
D. To increase the demand for petroleum products
Answer: B
Explanation:
Reusable bottles reduce the need for single-use plastics, which are often made from petroleum and contribute to environmental pollution. Choosing reusable items helps conserve resources, minimizes waste, and supports sustainable living practices.
Q. A lake begins drying up due to continuous overuse of water. Which lesson from Chapter 13 does this situation highlight?
A. Natural resources are unlimited.
B. Conservation of natural resources is essential.
C. Water has no role in supporting life.
D. Ecosystems remain unaffected by resource depletion.
Answer: B
Explanation:
Freshwater is a limited natural resource that must be used responsibly. Excessive extraction can reduce water availability, disturb aquatic ecosystems, and affect human life. Sustainable use and conservation are essential for maintaining environmental balance.
Q. Residents of a town separate biodegradable and non-biodegradable waste before disposal. Which environmental objective does this practice support?
A. Increasing land pollution
B. Efficient waste management and resource conservation
C. Reducing the amount of oxygen in the atmosphere
D. Increasing the use of non-renewable resources
Answer: B
Explanation:
Waste segregation makes recycling and composting more effective. Biodegradable waste can be converted into compost, while recyclable materials can be processed for reuse. This reduces landfill waste, conserves natural resources, and helps keep the environment clean.
Q. A school organizes a campaign encouraging students to save water, plant trees, and avoid littering. Which value is the campaign mainly promoting?
A. Exploitation of natural resources
B. Environmental responsibility and sustainable living
C. Increased consumption of fossil fuels
D. Reduction of biodiversity
Answer: B
Explanation:
Simple actions like saving water, planting trees, and keeping surroundings clean encourage responsible use of natural resources. These habits protect ecosystems, reduce pollution, and contribute to sustainable development, helping preserve Earth as a unique life-sustaining planet for future generations.
Why Practise These Chapter 13 MCQs?
Regular practice of Class 8 Science Chapter 13 MCQs with answers and explanations helps you revise the chapter more efficiently while improving your accuracy in objective questions. Instead of reading the same concepts repeatedly, MCQs encourage active recall, making revision faster and more effective.
These questions are useful for:
- CBSE Class 8 school examinations
- Unit tests and periodic assessments
- Half-yearly and annual exams
- Quick chapter revision
- Self-assessment after completing NCERT
- Building confidence before examinations
Since every answer includes a concise explanation, you can easily identify mistakes, strengthen weak areas, and gain a deeper understanding of the chapter.
Topics Covered in These MCQs
These MCQs comprehensively cover the important concepts from Our Home: Earth, a Unique Life Sustaining Planet, including:
- Earth as a unique life-sustaining planet
- Characteristics that make Earth suitable for life
- Atmosphere and its importance
- Hydrosphere and water resources
- Lithosphere and land resources
- Biosphere and living organisms
- Biodiversity and ecosystems
- Natural resources
- Sustainable use of resources
- Environmental conservation
- Human impact on the environment
- Importance of maintaining ecological balance
Practising questions from all these topics ensures complete chapter revision and better preparation for objective-based assessments.
Preparation Tips for Chapter 13 MCQs
Scoring well in Chapter 13 is easier when your preparation combines conceptual understanding with regular practice. Keep these tips in mind while revising:
- Read the NCERT chapter thoroughly before attempting MCQs.
- Understand the relationship between the atmosphere, hydrosphere, lithosphere, and biosphere.
- Focus on the reasons that make Earth a unique life-sustaining planet.
- Revise important scientific terms and definitions.
- Learn the importance of conserving natural resources.
- Carefully read every option before selecting an answer.
- Review the explanations after solving each question to strengthen your understanding.
- Practise chapter-wise MCQs regularly to improve speed and accuracy.
Consistent practice with well-explained questions is one of the most effective ways to prepare for school examinations.
