The following 20 Multiple Choice Questions (MCQ) are based on
Chapter 13: Our Home: Earth, a Unique Life Sustaining Planet from the NCERT Class 8
Science textbook Curiosity. Each question has four options - select the
best answer and click to check.
Instructions: Read each question carefully. Choose the most
appropriate option from (a), (b), (c), or (d). Click
Show Answer to reveal the correct answer with explanation.
Multiple Choice Questions
1Earth is unique among known planets because it:
(a) Supports abundant, diverse life
(b) Is the largest planet
(c) Is closest to the Sun
(d) Has no atmosphere
(a) is correct
Its interacting physical and biological conditions allow life as we know it to thrive.
2The thin region of Earth where life exists is called the:
(a) Core
(b) Mantle
(c) Orbit
(d) Biosphere
(d) is correct
The biosphere spans parts of land, water and air where organisms live.
3Earth's position in the Sun's habitable zone helps water remain:
(a) Only vapour
(b) Absent
(c) Liquid over much of the surface
(d) Only solid
(c) is correct
Temperatures at this distance permit long-lasting liquid water under suitable atmospheric pressure.
4Why is liquid water especially important for life?
(a) Only rocks use it
(b) It is a medium for biochemical reactions and transport
(c) It prevents every chemical reaction
(d) It supplies no matter
(b) is correct
Cells depend on water to dissolve, transport and react substances.
5Earth's atmosphere supports life by providing gases and:
(a) Regulating temperature and shielding harmful radiation
(b) Removing all pressure
(c) Blocking all sunlight
(d) Stopping weather
(a) is correct
The atmosphere moderates conditions while ozone and other processes reduce harmful radiation.
6Oxygen in Earth's atmosphere is used by many organisms for:
(a) Photosynthesis only
(b) Making rocks
(c) Stopping energy release
(d) Respiration
(d) is correct
Aerobic respiration releases usable energy from food.
7Carbon dioxide is essential to green plants for:
(a) Magnetism
(b) Locomotion
(c) Photosynthesis
(d) Hearing
(c) is correct
Plants use carbon dioxide and water to make food using light energy.
8Earth's suitable size helps it retain:
(a) Sunlight inside its core
(b) An atmosphere through gravity
(c) No gases at all
(d) Only solid water
(b) is correct
A sufficiently strong gravitational pull prevents atmospheric gases from escaping rapidly.
9Earth's magnetic field protects life mainly by deflecting:
(a) Many charged particles from the solar wind
(b) All visible light
(c) Ocean waves
(d) Sound waves
(a) is correct
The magnetosphere reduces erosion of the atmosphere and exposure to energetic charged particles.
10Soil supports terrestrial life by providing plants with:
(a) Only light
(b) No microorganisms
(c) A complete atmosphere
(d) Anchorage, water and mineral nutrients
(d) is correct
Soil links weathered rock, water, air, organic matter and living organisms.
11Microorganisms help sustain life by:
(a) Removing nitrogen from every ecosystem
(b) Preventing soil formation
(c) Decomposing matter and cycling nutrients
(d) Stopping all decay
(c) is correct
Microbial transformations return essential elements to forms usable by other organisms.
12A balanced ecosystem depends on:
(a) Absence of decomposers
(b) Interactions among organisms and physical conditions
(c) One species living alone
(d) Unlimited extraction of resources
(b) is correct
Energy flow, nutrient cycling and population interactions maintain ecosystem functioning.
13Reproduction ensures that:
(a) Life continues across generations
(b) Every organism lives forever
(c) Variation disappears
(d) Resources become unlimited
(a) is correct
New individuals replace those that die and pass biological information onward.
14Asexual reproduction usually involves:
(a) Fusion of two gametes
(b) Two parents in every case
(c) No transfer of hereditary information
(d) One parent and genetically similar offspring
(d) is correct
Offspring arise without gamete fusion and are generally close copies of the parent.
15Sexual reproduction generally produces greater variation because it:
(a) Makes exact copies only
(b) Prevents inheritance
(c) Combines genetic information from two gametes
(d) Uses no genetic material
(c) is correct
Mixing hereditary information creates new combinations of traits.
16Variation can help a species survive because:
(a) It stops reproduction
(b) Some individuals may suit changed conditions better
(c) All changes affect everyone identically
(d) It eliminates adaptation
(b) is correct
Diversity of traits increases the chance that some individuals withstand a new challenge.
17Which human activity is a major threat to habitats?
(a) Deforestation
(b) Habitat restoration
(c) Waste reduction
(d) Protected wildlife corridors
(a) is correct
Clearing natural vegetation destroys and fragments living space.
18Burning large amounts of fossil fuel threatens climate mainly by increasing:
(a) Atmospheric oxygen only
(b) Earth's distance from the Sun
(c) The Moon's mass
(d) Greenhouse gases such as carbon dioxide
(d) is correct
Extra greenhouse gases trap more outgoing heat and disturb climate patterns.
19Satellite false-colour images are useful because colours can represent:
(a) Imaginary planets
(b) No scientific data
(c) Different measured information such as vegetation or temperature
(d) Only what human eyes see
(c) is correct
Scientists assign colours to sensor measurements to reveal patterns not obvious in ordinary photographs.
20Which action best supports Earth's life-sustaining systems?
(a) Wasting fresh water
(b) Conserving habitats and using resources responsibly
(c) Increasing pollution
(d) Destroying food webs
(b) is correct
Conservation reduces pressures on biodiversity, climate, soil, air and water.
What is covered in CBSE Class 8 Science Chapter 13 Our Home: Earth, a Unique Life Sustaining Planet?
This chapter covers all key topics from Our Home: Earth, a Unique Life Sustaining Planet as per CBSE 2026-27 syllabus.
Is this MCQ Test useful for CBSE board exams?
Yes, designed for CBSE Class 8 board exam preparation covering the complete syllabus.
Are these CBSE Class 8 Science MCQ Test updated for 2026-27?
Yes, all content at eBookPublisher is updated as per the latest 2026-27 CBSE syllabus.
How many chapters are in CBSE Class 8 Science?
All chapters of CBSE Class 8 Science are covered at eBookPublisher with free MCQ Test for each chapter.
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