1. What does the term ‘environment’ include?
a) Only living things
b) Only non-living things
c) Both living and non-living things
d) Only atmosphere
Answer: c) Both living and non-living things
Explanation: Environment consists of biotic (living) and abiotic (non-living) components.
2. The scientific study of the relationship between organisms and their environment is called:
a) Zoology
b) Ecology
c) Botany
d) Geology
Answer: b) Ecology
Explanation: Ecology deals with interactions between living organisms and their surroundings.
3. The basic functional unit of ecology is:
a) Species
b) Population
c) Ecosystem
d) Community
Answer: c) Ecosystem
Explanation: Ecosystem includes both living organisms and their physical environment.
4. Which is NOT a component of the environment?
a) Atmosphere
b) Biosphere
c) Hydrosphere
d) Isosphere
Answer: d) Isosphere
Explanation: Isosphere is not an environmental component; key ones are atmosphere, lithosphere, hydrosphere, and biosphere.
5. Which of the following is a biotic factor?
a) Temperature
b) Light
c) Plants
d) Soil
Answer: c) Plants
Explanation: Biotic factors are living things such as plants, animals, and microbes.
6. The upper layer of the earth where living beings exist is called:
a) Lithosphere
b) Atmosphere
c) Biosphere
d) Hydrosphere
Answer: c) Biosphere
Explanation: Biosphere is the zone of life on Earth.
7. 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 continuously replenished by nature.
8. Who is known as the father of ecology?
a) Charles Darwin
b) Ernst Haeckel
c) Gregor Mendel
d) Rachel Carson
Answer: b) Ernst Haeckel
Explanation: He coined the term ‘ecology’ in 1866.
9. Which layer of the atmosphere contains the ozone layer?
a) Troposphere
b) Stratosphere
c) Mesosphere
d) Thermosphere
Answer: b) Stratosphere
Explanation: Ozone layer is found in the stratosphere and absorbs harmful UV rays.
10. The main cause of seasons on Earth is:
a) Earth’s rotation
b) Earth’s revolution and tilt of axis
c) Moon’s gravity
d) Sun’s movement
Answer: b) Earth’s revolution and tilt of axis
Explanation: Tilted axis and revolution cause varying sunlight distribution.
11. Which of the following is NOT a greenhouse gas?
a) Carbon dioxide
b) Methane
c) Nitrous oxide
d) Oxygen
Answer: d) Oxygen
Explanation: Oxygen does not trap heat; CO₂, CH₄, and N₂O are greenhouse gases.
12. Which term refers to all organisms of the same species in a given area?
a) Community
b) Population
c) Biosphere
d) Habitat
Answer: b) Population
Explanation: Population is a group of the same species living together.
13. What is the main source of energy for ecosystems?
a) Wind
b) Solar energy
c) Chemical energy
d) Geothermal energy
Answer: b) Solar energy
Explanation: Sunlight drives photosynthesis and energy flow in ecosystems.
14. The natural place where an organism lives is called:
a) Habitat
b) Niche
c) Community
d) Ecosystem
Answer: a) Habitat
Explanation: Habitat is the specific environment where an organism lives.
15. Which of the following is an abiotic factor?
a) Bacteria
b) Grass
c) Water
d) Insects
Answer: c) Water
Explanation: Abiotic factors are non-living elements of the environment.
16. The layer of gases surrounding Earth is called:
a) Lithosphere
b) Hydrosphere
c) Atmosphere
d) Troposphere
Answer: c) Atmosphere
Explanation: Atmosphere contains air essential for life.
17. Which sphere contains all the water on Earth?
a) Lithosphere
b) Hydrosphere
c) Atmosphere
d) Biosphere
Answer: b) Hydrosphere
Explanation: Hydrosphere includes oceans, rivers, lakes, and groundwater.
18. The gradual change in species composition in an area over time is called:
a) Succession
b) Evolution
c) Adaptation
d) Mutation
Answer: a) Succession
Explanation: Ecological succession involves replacement of species over time.
19. Which of the following is an example of a decomposer?
a) Cow
b) Mushroom
c) Grasshopper
d) Lion
Answer: b) Mushroom
Explanation: Decomposers break down dead organic matter into simpler substances.
20. Which of the following is NOT an ecosystem?
a) Forest
b) Pond
c) Desert
d) Table
Answer: d) Table
Explanation: Table is non-living and not a functional ecological unit.
21. In an ecosystem, plants are considered:
a) Consumers
b) Producers
c) Decomposers
d) Predators
Answer: b) Producers
Explanation: Plants produce food through photosynthesis and form the base of the food chain.
22. Which of the following is a primary consumer?
a) Rabbit
b) Lion
c) Eagle
d) Snake
Answer: a) Rabbit
Explanation: Primary consumers eat producers (plants).
23. Carnivores are:
a) Herbivores
b) Meat-eaters
c) Omnivores
d) Detritivores
Answer: b) Meat-eaters
Explanation: Carnivores feed on other animals.
24. Which of these is an example of a detritivore?
a) Earthworm
b) Deer
c) Tiger
d) Peacock
Answer: a) Earthworm
Explanation: Detritivores feed on dead organic matter.
25. The sequence of organisms through which energy flows is called:
a) Food chain
b) Food web
c) Pyramid
d) Biogeochemical cycle
Answer: a) Food chain
Explanation: Food chain shows energy transfer from one organism to another.
26. Which of these best represents reality in nature?
a) Food chain
b) Food web
c) Energy ladder
d) Straight chain
Answer: b) Food web
Explanation: In nature, food chains interconnect to form a food web.
27. Energy flow in an ecosystem is:
a) Cyclic
b) One-way
c) Random
d) Multi-directional
Answer: b) One-way
Explanation: Energy flows in one direction — from sun to producers to consumers.
28. Which law states that energy is neither created nor destroyed?
a) First law of thermodynamics
b) Second law of thermodynamics
c) Law of entropy
d) Law of gravity
Answer: a) First law of thermodynamics
Explanation: This law is about energy conservation.
29. Which pyramid is always upright?
a) Pyramid of numbers
b) Pyramid of biomass
c) Pyramid of energy
d) Pyramid of size
Answer: c) Pyramid of energy
Explanation: Energy decreases at each trophic level, so the pyramid is always upright.
30. Which of these is a secondary consumer?
a) Grass
b) Goat
c) Snake
d) Mushroom
Answer: c) Snake
Explanation: Snake feeds on primary consumers like frogs or mice.
31. The natural recycling of nutrients is known as:
a) Energy flow
b) Nutrient cycling
c) Photosynthesis
d) Succession
Answer: b) Nutrient cycling
Explanation: It involves continuous movement of nutrients like nitrogen and carbon.
32. Which gas is fixed during photosynthesis?
a) Nitrogen
b) Oxygen
c) Carbon dioxide
d) Methane
Answer: c) Carbon dioxide
Explanation: Plants use CO₂ to produce glucose.
33. The process of converting ammonia into nitrates is called:
a) Nitrogen fixation
b) Nitrification
c) Denitrification
d) Ammonification
Answer: b) Nitrification
Explanation: Nitrifying bacteria convert ammonia into nitrates.
34. In the carbon cycle, plants release CO₂ during:
a) Photosynthesis
b) Respiration
c) Transpiration
d) Germination
Answer: b) Respiration
Explanation: Plants respire and release carbon dioxide.
35. Which ecosystem has the highest productivity?
a) Desert
b) Tundra
c) Tropical rainforest
d) Grassland
Answer: c) Tropical rainforest
Explanation: High temperature, rainfall, and biodiversity boost productivity.
36. The largest biome on Earth is:
a) Desert
b) Ocean
c) Grassland
d) Forest
Answer: b) Ocean
Explanation: Oceans cover about 71% of Earth’s surface.
37. Which cycle involves evaporation, condensation, and precipitation?
a) Nitrogen cycle
b) Water cycle
c) Carbon cycle
d) Oxygen cycle
Answer: b) Water cycle
Explanation: The water cycle circulates water in different forms.
38. Which type of succession starts on bare rock?
a) Primary succession
b) Secondary succession
c) Tertiary succession
d) Climax succession
Answer: a) Primary succession
Explanation: Primary succession begins where there was no life before.
39. An organism’s role in its environment is called:
a) Habitat
b) Niche
c) Community
d) Population
Answer: b) Niche
Explanation: Niche refers to the functional role of a species.
40. Which organisms form the first trophic level?
a) Herbivores
b) Producers
c) Carnivores
d) Omnivores
Answer: b) Producers
Explanation: Producers convert solar energy into chemical energy.
41. Which is NOT a non-renewable resource?
a) Coal
b) Petroleum
c) Natural gas
d) Wind energy
Answer: d) Wind energy
Explanation: Wind is a renewable resource.
42. Which is the most abundant gas in the atmosphere?
a) Oxygen
b) Nitrogen
c) Carbon dioxide
d) Argon
Answer: b) Nitrogen
Explanation: Nitrogen makes up about 78% of Earth’s atmosphere.
43. Biodiversity refers to:
a) Number of people in an area
b) Variety of life forms
c) Amount of forest cover
d) Climate change
Answer: b) Variety of life forms
Explanation: Biodiversity is the diversity of species, genes, and ecosystems.
44. Which country has the highest biodiversity?
a) Brazil
b) India
c) Australia
d) Canada
Answer: a) Brazil
Explanation: Brazil, especially the Amazon, has the richest biodiversity.
45. India is one of the world’s:
a) Biodiversity hotspots
b) Desert countries
c) Polar regions
d) Low-biodiversity areas
Answer: a) Biodiversity hotspots
Explanation: India has 4 biodiversity hotspots.
46. Which forest type is known as the ‘lungs of the planet’?
a) Coniferous forest
b) Tropical rainforest
c) Temperate forest
d) Mangroves
Answer: b) Tropical rainforest
Explanation: They absorb CO₂ and release O₂ in large amounts.
47. Which of these is an endemic species in India?
a) Lion-tailed macaque
b) Tiger
c) Leopard
d) Elephant
Answer: a) Lion-tailed macaque
Explanation: Found only in the Western Ghats.
48. The Sundarbans are famous for:
a) Elephants
b) Royal Bengal tigers
c) Snow leopards
d) Rhinos
Answer: b) Royal Bengal tigers
Explanation: The mangrove forests are home to this tiger species.
49. Which plant is known as the ‘Queen of Herbs’?
a) Neem
b) Tulsi
c) Aloe vera
d) Rose
Answer: b) Tulsi
Explanation: Tulsi has medicinal value in Ayurveda.
50. Which is the smallest biosphere reserve in India?
a) Dibru-Saikhowa
b) Panna
c) Nilgiri
d) Dihang-Dibang
Answer: b) Panna
Explanation: Located in Madhya Pradesh.
51. Which of these is an example of an extinct species?
a) Dodo
b) Tiger
c) Panda
d) Deer
Answer: a) Dodo
Explanation: Dodo bird is no longer found on Earth.
52. Which is the largest coral reef system in the world?
a) Red Sea Reef
b) Great Barrier Reef
c) Lakshadweep Reef
d) Belize Reef
Answer: b) Great Barrier Reef
Explanation: Located off Australia’s coast.
53. Which plant is known for nitrogen fixation?
a) Wheat
b) Rice
c) Legumes
d) Maize
Answer: c) Legumes
Explanation: Leguminous plants have nitrogen-fixing bacteria in root nodules.
54. Which resource is obtained from bauxite?
a) Iron
b) Copper
c) Aluminium
d) Gold
Answer: c) Aluminium
Explanation: Bauxite is the ore of aluminium.
55. Which is the largest source of freshwater on Earth?
a) Rivers
b) Lakes
c) Ice caps and glaciers
d) Groundwater
Answer: c) Ice caps and glaciers
Explanation: They store most of the Earth’s freshwater.
56. Which state in India has the highest forest cover?
a) Arunachal Pradesh
b) Madhya Pradesh
c) Mizoram
d) Assam
Answer: b) Madhya Pradesh
Explanation: As per Forest Survey of India.
57. Which is the main cause of deforestation?
a) Industrialization
b) Agriculture expansion
c) Urbanization
d) All of the above
Answer: d) All of the above
Explanation: Multiple human activities cause deforestation.
58. The Gir Forest is famous for:
a) Asiatic lions
b) Tigers
c) Leopards
d) Elephants
Answer: a) Asiatic lions
Explanation: Gir in Gujarat is the only natural home of Asiatic lions.
59. Which is the largest mangrove forest in the world?
a) Sundarbans
b) Bhitarkanika
c) Pichavaram
d) Amazon Delta
Answer: a) Sundarbans
Explanation: Spread over India and Bangladesh.
60. Which is NOT a fossil fuel?
a) Coal
b) Oil
c) Natural gas
d) Uranium
Answer: d) Uranium
Explanation: Uranium is used in nuclear power, not a fossil fuel.
61. The major cause of acid rain is:
a) CO₂
b) SO₂ and NOx
c) CH₄
d) O₃
Answer: b) SO₂ and NOx – These gases form acids in rainwater.
62. Which is the main gas responsible for global warming?
a) O₂
b) CO₂
c) N₂
d) Ar
Answer: b) CO₂ – Traps infrared radiation.
63. Smog is a mixture of:
a) Smoke and fog
b) Dust and air
c) Water and dust
d) Fog and rain
Answer: a) Smoke and fog.
64. Which disease is caused by water pollution?
a) Cholera
b) Asthma
c) Tuberculosis
d) Diabetes
Answer: a) Cholera.
65. Minamata disease is caused by:
a) Lead
b) Mercury
c) Arsenic
d) Cadmium
Answer: b) Mercury – Affected Japan’s Minamata Bay.
66. Which is a biodegradable pollutant?
a) Plastic
b) Pesticides
c) Paper
d) Lead
Answer: c) Paper – Can be decomposed naturally.
67. The ozone hole is largest over:
a) North Pole
b) Antarctica
c) Equator
d) Europe
Answer: b) Antarctica.
68. Which protocol addresses ozone depletion?
a) Kyoto Protocol
b) Montreal Protocol
c) Paris Agreement
d) Rio Declaration
Answer: b) Montreal Protocol – 1987 agreement.
69. Which protocol focuses on climate change?
a) Kyoto Protocol
b) Montreal Protocol
c) Basel Convention
d) Nagoya Protocol
Answer: a) Kyoto Protocol.
70. Which gas is measured in Air Quality Index (AQI)?
a) CO
b) SO₂
c) PM2.5
d) All of these
Answer: d) All of these – AQI includes multiple pollutants.
71. Which of these is an in-situ conservation method?
a) Zoo
b) Botanical garden
c) National park
d) Gene bank
Answer: c) National park – Conserves species in their habitat.
72. Which is NOT an effect of noise pollution?
a) Hearing loss
b) Hypertension
c) Increased crop yield
d) Stress
Answer: c) Increased crop yield.
73. Bhopal gas tragedy involved leakage of:
a) Methyl isocyanate
b) Ammonia
c) Chlorine
d) Sulphur dioxide
Answer: a) Methyl isocyanate.
74. Which year was the Environment Protection Act passed in India?
a) 1972
b) 1986
c) 1992
d) 2000
Answer: b) 1986.
75. Ganga Action Plan was launched in:
a) 1980
b) 1985
c) 1990
d) 2000
Answer: b) 1985.
76. The agency monitoring air quality in India is:
a) BARC
b) CPCB
c) DRDO
d) CSIR
Answer: b) CPCB – Central Pollution Control Board.
77. Which renewable energy is generated from moving air?
a) Solar
b) Wind
c) Hydro
d) Geothermal
Answer: b) Wind.
78. Which renewable energy source uses heat from Earth’s interior?
a) Solar
b) Wind
c) Geothermal
d) Biomass
Answer: c) Geothermal.
79. Which energy source comes from organic matter?
a) Solar
b) Biomass
c) Hydro
d) Nuclear
Answer: b) Biomass.
80. The first Earth Summit was held in:
a) 1990, Tokyo
b) 1992, Rio de Janeiro
c) 1995, Paris
d) 2000, New York
Answer: b) 1992, Rio de Janeiro.
81. Which is the cleanest fossil fuel?
a) Coal
b) Oil
c) Natural gas
d) Peat
Answer: c) Natural gas.
82. Which city hosted the Paris Climate Agreement?
a) London
b) Paris
c) Rome
d) Geneva
Answer: b) Paris – 2015.
83. Which of these is NOT a greenhouse gas?
a) CH₄
b) CO₂
c) N₂
d) N₂O
Answer: c) N₂.
84. The Intergovernmental Panel on Climate Change (IPCC) was established in:
a) 1970
b) 1988
c) 1992
d) 2000
Answer: b) 1988.
85. Fly ash is produced by:
a) Nuclear plants
b) Thermal power plants
c) Hydropower plants
d) Solar plants
Answer: b) Thermal power plants.
86. Which is a non-point source of pollution?
a) Factory chimney
b) Vehicle exhaust
c) Agricultural runoff
d) Sewage outlet
Answer: c) Agricultural runoff.
87. Which of these is the largest source of marine pollution?
a) Oil spills
b) Plastic waste
c) Sewage discharge
d) Chemical dumping
Answer: c) Sewage discharge.
88. Which term refers to species at risk of extinction?
a) Endangered
b) Vulnerable
c) Extinct
d) Exotic
Answer: a) Endangered.
89. Which instrument measures noise levels?
a) Hygrometer
b) Decibel meter
c) Barometer
d) Lux meter
Answer: b) Decibel meter.
90. Which plant helps control water pollution?
a) Water hyacinth
b) Cactus
c) Neem
d) Bamboo
Answer: a) Water hyacinth.
91. Which is NOT a conventional source of energy?
a) Coal
b) Oil
c) Solar
d) Natural gas
Answer: c) Solar.
92. Which year was Project Tiger launched in India?
a) 1973
b) 1980
c) 1990
d) 2000
Answer: a) 1973.
93. Which is the largest source of freshwater pollution in India?
a) Industrial waste
b) Agricultural runoff
c) Domestic sewage
d) Thermal waste
Answer: c) Domestic sewage.
94. Which term refers to planting trees to restore forests?
a) Deforestation
b) Afforestation
c) Desertification
d) Reclamation
Answer: b) Afforestation.
95. Which law deals with wildlife protection in India?
a) Forest Act
b) Wildlife Protection Act
c) Environment Protection Act
d) Biodiversity Act
Answer: b) Wildlife Protection Act – Enacted in 1972.
96. Which animal is the national aquatic animal of India?
a) Crocodile
b) Dolphin
c) Tortoise
d) Shark
Answer: b) Dolphin.
97. Which is a renewable source of energy?
a) Coal
b) Solar
c) Petroleum
d) Natural gas
Answer: b) Solar.
98. Which pollutant is responsible for ‘Itai-Itai’ disease?
a) Mercury
b) Cadmium
c) Lead
d) Arsenic
Answer: b) Cadmium.
99. Which is the world’s largest terrestrial biome?
a) Tundra
b) Taiga (Boreal forest)
c) Desert
d) Grassland
Answer: b) Taiga.
100. Which is NOT a function of forests?
a) Carbon sequestration
b) Soil erosion prevention
c) Oxygen production
d) Increasing desertification
Answer: d) Increasing desertification
Explanation: Forests prevent desertification.