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Our Environment — Class 10 CBSE Science MCQs with Solutions
Free Class 10 CBSE Science Our Environment MCQs with step-by-step solutions. Practise online on Prepizo — no login needed.
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Sample questions with solutions
Q1 — easy
Functional self-sustaining ecological unit consisting of biotic and abiotic components interacting together is an:
A. Population
B. Ecosystem ✓ Correct
C. Biome
D. Community
Solution: An ecosystem includes living organisms and non-living environment.
Q2 — easy
Organisms that manufacture organic food from inorganic substances using solar light are:
A. Consumers
B. Producers (Autotrophs) ✓ Correct
C. Decomposers
D. Herbivores
Solution: Green plants and photosynthetic bacteria are producers.
Q3 — easy
Micro-organisms like bacteria and fungi that break down dead organic remains into soil nutrients are:
A. Producers
B. Decomposers ✓ Correct
C. Primary consumers
D. Parasites
Solution: Decomposers recycle organic nutrients back into abiotic pool.
Q4 — easy
In a food chain, maximum energy is available at which trophic level?
A. Primary consumers
B. Producers (Trophic Level 1) ✓ Correct
C. Secondary consumers
D. Tertiary consumers
Solution: Producers capture solar energy first and hold maximum energy.
Q5 — easy
According to Lindeman's 10% Law of energy transfer in food chains, percentage of energy transferred to next higher trophic level is:
A. 1%
B. 10% ✓ Correct
C. 50%
D. 90%
Solution: Only 10% of energy is passed on to the next trophic level.
Q6 — easy
Green plants in a terrestrial ecosystem capture roughly what percentage of sunlight falling on their leaves?
A. 1% ✓ Correct
B. 10%
C. 50%
D. 100%
Solution: Plants absorb only ~1% of incident solar energy for photosynthesis.
Q7 — easy
Phenomenon of progressive accumulation of non-biodegradable toxic chemicals (like DDT) at successive higher trophic levels is:
A. Eutrophication
B. Biological Magnification ✓ Correct
C. Bio-degradation
D. Pollution
Solution: Biomagnification concentrates toxins up the food chain.
Q8 — easy
Top-level carnivores (like humans, hawks) suffer maximum toxic accumulation due to:
A. Eutrophication
B. Biological Magnification ✓ Correct
C. Photosynthesis
D. Decomposition
Solution: Toxins accumulate most at the top trophic level.
Q9 — easy
Ozone layer (O₃) present in Stratosphere protects Earth's biosphere from harmful solar:
A. Infrared rays
B. Ultraviolet (UV) radiation ✓ Correct
C. Gamma rays
D. X-rays
Solution: Ozone layer absorbs harmful UV-B and UV-C solar radiation.
Q10 — easy
Synthetic chemical compounds primarily responsible for depletion of stratospheric Ozone layer are:
A. CFCs (Chlorofluorocarbons) ✓ Correct
B. DDT
C. Carbon dioxide
D. Methane
Solution: CFCs release chlorine radicals that destroy ozone molecules.
Q11 — easy
UNEP successfully forged an international agreement in 1987 to freeze CFC production at 1986 levels. Expanded form of UNEP is:
A. United Nations Energy Program
B. United Nations Environment Programme ✓ Correct
C. Universal National Environment Project
D. United Nations Eco Preservation
Solution: UNEP = United Nations Environment Programme.
Q12 — easy
Waste substances that CANNOT be broken down by biological action of saprophytes/bacteria are:
A. Biodegradable wastes
B. Non-biodegradable wastes ✓ Correct
C. Organic wastes
D. Compostable wastes
Solution: Plastics, glass, and metals are non-biodegradable.
Q13 — easy
Which of the following is a BIODEGRADABLE waste material?
A. Plastic bag
B. Fruit peels and paper ✓ Correct
C. Glass bottle
D. DDT powder
Solution: Organic plant matter decomposes naturally.
Q14 — easy
Interconnected network of multiple food chains in an ecosystem forms a:
A. Trophic level
B. Food web ✓ Correct
C. Food pyramid
D. Biosphere
Solution: A food web integrates overlapping food chains.
Q15 — easy
If 10,000 J of energy is available at producer level (plants), energy available to primary consumers (herbivores) is:
A. 10,000 J
B. 1000 J ✓ Correct
C. 100 J
D. 10 J
Solution: 10% of 10,000 J = 1000 J.