Class 10 Science NCERT MCQs Chapter 13 Our Environment
NCERT MCQs of Class 10 Science, Chapter 13, Our Environment
1) Which of the following is a biotic component of the environment?
a) Soil
b) Water
c) Plants
d) Air
Answer: c) Plants
Explanation: Biotic components include living organisms like plants, animals, and microbes, while abiotic components include non-living things like water, soil, and air.2) Which of the following is an example of a decomposer?
a) Cow
b) Grass
c) Fungi
d) Eagle
Answer: c) Fungi
Explanation: Decomposers like fungi and bacteria break down organic matter into simpler substances, recycling nutrients into the ecosystem.3) Which of these organisms is a primary consumer?
a) Grass
b) Deer
c) Lion
d) Vulture
Answer: b) Deer
Explanation: Primary consumers are herbivores that feed on producers (plants). Deer eat grass, making them primary consumers.4) What is the ultimate source of energy for all living organisms?
a) Water
b) Plants
c) Sun
d) Air
Answer: c) Sun
Explanation: The Sun is the primary source of energy, as plants use sunlight to make food through photosynthesis.5) Which of the following forms the base of an ecological pyramid?
a) Carnivores
b) Herbivores
c) Producers
d) Decomposers
Answer: c) Producers
Explanation: Producers (plants and algae) form the base of an ecological pyramid because they synthesize their own food.6) What is the role of decomposers in an ecosystem?
a) Fix nitrogen
b) Convert sunlight into energy
c) Recycle nutrients
d) Act as primary producers
Answer: c) Recycle nutrients
Explanation: Decomposers break down dead organisms and recycle nutrients back into the soil, making them available for producers.7) Which of the following is an example of a non-biodegradable substance?
a) Paper
b) Plastic
c) Cotton
d) Vegetable peels
Answer: b) Plastic
Explanation: Plastic is non-biodegradable, meaning it does not decompose naturally and remains in the environment for a long time.8) Which of the following is a biodegradable waste?
a) Glass
b) Aluminium foil
c) Fruit peels
d) Plastic bottle
Answer: c) Fruit peels
Explanation: Biodegradable waste decomposes naturally by microorganisms. Fruit peels break down into organic matter.9) What happens to energy as we move up in a food chain?
a) Increases
b) Decreases
c) Remains constant
d) Gets recycled
Answer: b) Decreases
Explanation: According to the 10% Law, only 10% of energy is passed to the next trophic level, and the rest is lost as heat.10) Which of these is an example of a food chain?
a) Grass → Deer → Tiger
b) Fish → Grass → Human
c) Sun → Soil → Tree
d) Lion → Goat → Grass
Answer: a) Grass → Deer → Tiger
Explanation: A food chain follows energy flow from producers (grass) → primary consumers (deer) → secondary consumers (tiger).11) Which gas is mainly responsible for the greenhouse effect?
a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Hydrogen
Answer: b) Carbon dioxide
Explanation: Carbon dioxide (CO₂) traps heat in the Earth's atmosphere, leading to global warming.12) What happens if all the decomposers are removed from an ecosystem?
a) The food chain will stop
b) Nutrients will not be recycled
c) Plants will stop growing
d) All of the above
Answer: d) All of the above
Explanation: Without decomposers, nutrients will not return to the soil, affecting plant growth and the entire food chain.13) What is biomagnification?
a) Increase in pollution
b) Increase in population
c) Increase in toxic substances in a food chain
d) Increase in oxygen levels
Answer: c) Increase in toxic substances in a food chain
Explanation: Biomagnification is the accumulation of toxic substances (like pesticides) at higher trophic levels.14) Which of the following is an example of a secondary consumer?
a) Grass
b) Cow
c) Snake
d) Earthworm
Answer: c) Snake
Explanation: Secondary consumers eat primary consumers. Snakes eat herbivores like rats, making them secondary consumers.15) Which of the following is NOT a reason for environmental pollution?
a) Industrial waste
b) Deforestation
c) Afforestation
d) Burning of fossil fuels
Answer: c) Afforestation
Explanation: Afforestation (planting trees) helps reduce pollution by absorbing carbon dioxide.16) Which of the following pollutants is responsible for ozone layer depletion?
a) Carbon dioxide
b) CFCs (Chlorofluorocarbons)
c) Nitrogen dioxide
d) Methane
Answer: b) CFCs (Chlorofluorocarbons)
Explanation: CFCs, found in refrigerants and aerosol sprays, destroy the ozone layer.17) Which gas is responsible for acid rain?
a) Oxygen
b) Sulfur dioxide
c) Nitrogen
d) Helium
Answer: b) Sulfur dioxide
Explanation: Sulfur dioxide (SO₂) reacts with water in the atmosphere to form acid rain.18) Which of the following causes soil pollution?
a) Use of organic manure
b) Excessive use of chemical fertilizers
c) Crop rotation
d) Planting trees
Answer: b) Excessive use of chemical fertilizers
Explanation: Chemical fertilizers disturb soil composition, leading to soil pollution.19) Which of the following is a renewable resource?
a) Coal
b) Petroleum
c) Solar energy
d) Natural gas
Answer: c) Solar energy
Explanation: Solar energy is renewable because it is inexhaustible and does not get depleted.20) Which of the following is the best way to reduce environmental pollution?
a) Using more plastic
b) Increasing deforestation
c) Reducing, reusing, and recycling waste
d) Burning more fossil fuels
Answer: c) Reducing, reusing, and recycling waste
Explanation: The 3Rs (Reduce, Reuse, Recycle) help minimize waste and pollution.
21) Which of the following organisms occupies the highest trophic level in a food chain?
a) Grass
b) Deer
c) Tiger
d) Rabbit
Answer: c) Tiger
Explanation: The tiger is a top predator (tertiary consumer) and occupies the highest trophic level in a food chain.
22) What is the main reason behind deforestation?
a) Soil conservation
b) Agriculture and urbanization
c) Increasing oxygen levels
d) Reducing carbon dioxide levels
Answer: b) Agriculture and urbanization
Explanation: Deforestation occurs mainly due to agriculture, urban expansion, and industrialization.
23) Which of the following is NOT an effect of deforestation?
a) Loss of biodiversity
b) Increase in greenhouse gases
c) Soil erosion
d) Increase in oxygen levels
Answer: d) Increase in oxygen levels
Explanation: Deforestation decreases oxygen levels by reducing the number of trees that produce oxygen through photosynthesis.
24) What is an ecological pyramid?
a) A graphical representation of energy flow in an ecosystem
b) A structure made by decomposers
c) A food storage system for animals
d) A type of biome
Answer: a) A graphical representation of energy flow in an ecosystem
Explanation: Ecological pyramids show energy, biomass, or number of organisms at each trophic level.
25) Which of the following is an example of a natural pollutant?
a) Smoke from industries
b) Volcanic ash
c) Plastic waste
d) Chemical fertilizers
Answer: b) Volcanic ash
Explanation: Volcanic ash is a natural pollutant, whereas others are man-made pollutants.
26) Which trophic level has the most energy available?
a) Producers
b) Primary consumers
c) Secondary consumers
d) Tertiary consumers
Answer: a) Producers
Explanation: According to the 10% Law, producers receive the most energy from the Sun, and only 10% is passed to each successive level.
27) Which of the following gases contributes to global warming?
a) Oxygen
b) Nitrogen
c) Carbon dioxide
d) Argon
Answer: c) Carbon dioxide
Explanation: Carbon dioxide (CO₂) traps heat in the atmosphere, causing global warming.
28) Which human activity does NOT contribute to air pollution?
a) Burning fossil fuels
b) Using bicycles
c) Deforestation
d) Industrial emissions
Answer: b) Using bicycles
Explanation: Bicycles do not produce pollutants, making them an eco-friendly mode of transport.
29) Which of the following is NOT a greenhouse gas?
a) Methane
b) Oxygen
c) Carbon dioxide
d) Water vapor
Answer: b) Oxygen
Explanation: Greenhouse gases trap heat in the atmosphere. Oxygen does not contribute to the greenhouse effect.
30) What is the main cause of ozone layer depletion?
a) Burning fossil fuels
b) Acid rain
c) Release of CFCs
d) Deforestation
Answer: c) Release of CFCs
Explanation: Chlorofluorocarbons (CFCs) break down the ozone layer, allowing harmful UV rays to reach Earth.
31) Which level of the food chain has the least energy available?
a) Producers
b) Primary consumers
c) Secondary consumers
d) Tertiary consumers
Answer: d) Tertiary consumers
Explanation: Tertiary consumers (top predators) receive the least energy because energy is lost at each trophic level.
32) Which of the following is NOT an effect of water pollution?
a) Death of aquatic life
b) Increased oxygen levels
c) Spread of waterborne diseases
d) Contamination of drinking water
Answer: b) Increased oxygen levels
Explanation: Water pollution reduces oxygen levels, leading to dead zones where aquatic life cannot survive.
33) Why is the use of paper bags preferred over plastic bags?
a) Paper bags are cheaper
b) Paper bags are more durable
c) Paper bags are biodegradable
d) Paper bags are waterproof
Answer: c) Paper bags are biodegradable
Explanation: Paper bags decompose naturally, whereas plastic bags pollute the environment.
34) Which of the following best describes a food web?
a) A single food chain
b) Interconnected food chains
c) A pyramid showing energy flow
d) A cycle of water movement
Answer: b) Interconnected food chains
Explanation: A food web consists of multiple food chains linked together, showing the interdependence of organisms.
35) Which of the following human activities can help conserve the environment?
a) Using plastic bags
b) Planting more trees
c) Deforestation
d) Burning more coal
Answer: b) Planting more trees
Explanation: Afforestation (planting trees) helps reduce carbon dioxide levels and prevents soil erosion.
36) Which of the following is a consequence of eutrophication?
a) Increase in oxygen levels
b) Increase in aquatic life
c) Death of fish due to oxygen depletion
d) Decrease in nutrient levels
Answer: c) Death of fish due to oxygen depletion
Explanation: Eutrophication occurs when excess nutrients in water bodies cause algal blooms, leading to oxygen depletion and the death of aquatic organisms.
37) Which of the following pollutants is mainly responsible for smog?
a) Sulfur dioxide
b) Nitrogen oxides
c) Carbon monoxide
d) Lead
Answer: b) Nitrogen oxides
Explanation: Nitrogen oxides (NOx) react with sunlight to form photochemical smog, which affects air quality.
38) What is the best way to manage non-biodegradable waste?
a) Burn it in open spaces
b) Dump it into rivers
c) Recycle and reuse it
d) Leave it in landfills
Answer: c) Recycle and reuse it
Explanation: Recycling and reusing non-biodegradable waste reduce environmental pollution.
39) Which of the following does NOT affect biodiversity?
a) Pollution
b) Habitat destruction
c) Sustainable farming
d) Climate change
Answer: c) Sustainable farming
Explanation: Sustainable farming protects biodiversity by reducing soil degradation and preserving ecosystems.
40) Which environmental issue is caused by excessive deforestation?
a) Acid rain
b) Global warming
c) Ozone layer depletion
d) Water pollution
Answer: b) Global warming
Explanation: Deforestation increases carbon dioxide levels, which contributes to global warming.
41) Which of the following best describes a biodegradable substance?
a) It does not decompose naturally
b) It can be broken down by microorganisms
c) It lasts for thousands of years
d) It causes pollution
Answer: b) It can be broken down by microorganisms
Explanation: Biodegradable substances decompose naturally due to the action of bacteria and fungi, returning nutrients to the environment.
42) Which of the following is NOT a measure to control water pollution?
a) Treating sewage before discharge
b) Using chemical pesticides in agriculture
c) Reducing industrial waste dumping
d) Promoting rainwater harvesting
Answer: b) Using chemical pesticides in agriculture
Explanation: Chemical pesticides contaminate water bodies, leading to water pollution.
43) Which of the following is the best example of a secondary consumer?
a) Grass
b) Deer
c) Snake
d) Eagle
Answer: c) Snake
Explanation: Secondary consumers feed on primary consumers (herbivores). Snakes eat rats and other small animals, making them secondary consumers.
44) Which of the following contributes the most to soil erosion?
a) Planting trees
b) Overgrazing by cattle
c) Using organic fertilizers
d) Practicing crop rotation
Answer: b) Overgrazing by cattle
Explanation: Overgrazing removes vegetation cover, making soil vulnerable to erosion by wind and water.
45) What is the main goal of sustainable development?
a) Rapid industrialization
b) Economic growth without environmental protection
c) Meeting present needs without compromising future generations
d) Increasing fossil fuel consumption
Answer: c) Meeting present needs without compromising future generations
Explanation: Sustainable development ensures that natural resources are used responsibly so they remain available for future generations.
46) Which of the following human activities contributes the most to desertification?
a) Water conservation
b) Afforestation
c) Over-cultivation and deforestation
d) Waste recycling
Answer: c) Over-cultivation and deforestation
Explanation: Over-cultivation and deforestation reduce soil fertility, leading to desertification.
47) Which of the following is a greenhouse gas?
a) Nitrogen
b) Helium
c) Methane
d) Oxygen
Answer: c) Methane
Explanation: Methane (CH₄) is a potent greenhouse gas released from livestock farming and decaying organic matter.
48) Which of the following activities does NOT help in reducing pollution?
a) Using public transport
b) Increasing waste recycling
c) Using plastic bags
d) Planting trees
Answer: c) Using plastic bags
Explanation: Plastic bags cause pollution as they are non-biodegradable and contribute to land and water pollution.
49) Which type of waste is generated in hospitals and medical facilities?
a) E-waste
b) Biomedical waste
c) Plastic waste
d) Radioactive waste
Answer: b) Biomedical waste
Explanation: Biomedical waste includes used syringes, gloves, bandages, and medical chemicals, which must be disposed of safely.
50) Which of the following is an example of an alternative energy source?
a) Coal
b) Petroleum
c) Wind energy
d) Natural gas
Answer: c) Wind energy
Explanation: Wind energy is renewable and does not contribute to pollution, making it an excellent alternative energy source.
51) Which of the following practices leads to an increase in soil fertility?
a) Deforestation
b) Excessive use of chemical fertilizers
c) Crop rotation
d) Overgrazing
Answer: c) Crop rotation
Explanation: Crop rotation maintains soil nutrients and prevents soil depletion, improving soil fertility.
52) Why is excessive use of pesticides harmful to the environment?
a) It improves crop yield
b) It increases soil fertility
c) It causes soil and water pollution
d) It promotes plant growth
Answer: c) It causes soil and water pollution
Explanation: Pesticides contaminate soil and water, harming plants, animals, and humans.
53) Which practice helps in reducing food waste?
a) Throwing away leftovers
b) Practicing composting
c) Overbuying groceries
d) Keeping food in plastic bags
Answer: b) Practicing composting
Explanation: Composting turns food waste into organic fertilizer, reducing waste and enriching soil.
54) What is the main cause of land pollution?
a) Proper waste disposal
b) Recycling
c) Deforestation and dumping of waste
d) Using biodegradable materials
Answer: c) Deforestation and dumping of waste
Explanation: Land pollution occurs due to deforestation, industrial waste, and improper disposal of garbage.
55) Which of the following is the best way to conserve biodiversity?
a) Hunting animals
b) Destroying forests
c) Establishing wildlife sanctuaries
d) Increasing pollution
Answer: c) Establishing wildlife sanctuaries
Explanation: Wildlife sanctuaries protect endangered species and help conserve biodiversity.
56) Which of the following is a natural method of waste disposal?
a) Incineration
b) Composting
c) Landfills
d) Dumping in rivers
Answer: b) Composting
Explanation: Composting is a natural waste disposal method that converts organic waste into nutrient-rich manure.
57) Which of the following pollutants is responsible for acid rain?
a) Nitrogen dioxide and sulfur dioxide
b) Oxygen and nitrogen
c) Methane and helium
d) Hydrogen and carbon monoxide
Answer: a) Nitrogen dioxide and sulfur dioxide
Explanation: Sulfur dioxide (SO₂) and nitrogen dioxide (NO₂) react with water vapor to form acid rain.
58) Which human activity leads to ozone depletion?
a) Use of solar panels
b) Planting trees
c) Use of CFC-based products
d) Using bicycles
Answer: c) Use of CFC-based products
Explanation: Chlorofluorocarbons (CFCs) from refrigerators and aerosol sprays break down the ozone layer.
59) What is the primary cause of the increase in Earth's temperature?
a) Acid rain
b) Deforestation and greenhouse gas emissions
c) Ozone formation
d) Overuse of groundwater
Answer: b) Deforestation and greenhouse gas emissions
Explanation: Deforestation and excessive greenhouse gas emissions trap heat, leading to global warming.
60) Which of the following is the best way to reduce plastic pollution?
a) Burning plastic waste
b) Recycling and using alternatives like cloth bags
c) Throwing plastic into rivers
d) Increasing plastic production
Answer: b) Recycling and using alternatives like cloth bags
Explanation: Recycling plastic and using biodegradable alternatives help reduce plastic pollution.
Exercise MCQs Solutions
1) Which of the following groups contain only biodegradable items?
a) Grass, flowers, and leather
b) Grass, wood, and plastic
c) Fruit peels, cake, and lime juice
d) Cake, wood, and grass
Answer: c) Fruit peels, cake, and lime juice
Explanation:Biodegradable substances can be broken down naturally by microorganisms.
Fruit peels, cake, and lime juice decompose quickly, while plastic and leather are non-biodegradable.
Hence, option (c) is correct.
2) Which of
the following constitutes a food chain?
a) Grass,
wheat, and mango
b) Grass, goat, and human
c) Goat, cow,
and elephant
d) Grass, fish, and goat
Answer:
b) Grass, goat, and human
Explanation:
A food chain represents the flow of energy from producers to consumers.
Grass (producer) → Goat (primary consumer) → Human (secondary consumer) forms a correct food chain.
Hence, option (b) is correct.
3) Which of
the following are environment-friendly practices?
a)
Carrying cloth bags while shopping
b) Switching off unnecessary
lights and fans
c) Walking to school instead of using a
scooter
d) All of the above
Answer: d) All
of the above
Explanation:
Using cloth bags reduces plastic waste.
Switching off lights and fans saves energy.
Walking instead of using a vehicle reduces air pollution.
All the given options are environment-friendly, so (d) is the correct answer.
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