50 Environment and Ecology MCQ with Answers – UPSC, Competitive Exams, Biodiversity & Climate Change

Environment and ecology form the backbone of sustainable development, balancing human needs with the preservation of biodiversity and natural processes. From the intricate food webs of forests to global drivers of climate change, mastering these concepts is crucial for UPSC and other competitive exams. Test your expertise on key topics such as biogeochemical cycles, conservation strategies, endangered species, and climate dynamics with these 50 MCQs—each complete with instant feedback to reinforce learning. Dive in and strengthen your command over the planet’s vital systems!

50 Environment and Ecology MCQs with Answers

1. Which cycle involves the conversion of atmospheric nitrogen into ammonia by soil bacteria?

• A. Carbon cycle
• B. Nitrogen cycle
• C. Phosphorus cycle
• D. Sulfur cycle

2. What term describes species unique to a particular geographic region?

• A. Indigenous
• B. Cosmopolitan
• C. Endemic
• D. Exotic

3. Which gas is most responsible for anthropogenic global warming?

• A. Carbon dioxide (CO₂)
• B. Nitrous oxide (N₂O)
• C. Methane (CH₄)
• D. Ozone (O₃)

4. Which ecosystem has the highest primary productivity?

• A. Desert
• B. Tundra
• C. Open ocean
• D. Tropical rainforest

5. Which protocol aims to reduce emissions of sulfur and nitrogen oxides?

• A. Kyoto Protocol
• B. Gothenburg Protocol
• C. Montreal Protocol
• D. Paris Agreement

6. What is the primary cause of coral bleaching?

• A. Oil spills
• B. Overfishing
• C. Elevated sea temperatures
• D. Nutrient enrichment

7. Which trophic level comprises primary consumers?

• A. Herbivores
• B. Carnivores
• C. Decomposers
• D. Producers

8. Which reserve is India’s first Tiger Reserve?

• A. Sundarbans
• B. Kanha
• C. Ranthambore
• D. Jim Corbett

9. The ozone layer is located in which part of the atmosphere?

• A. Troposphere
• B. Stratosphere
• C. Mesosphere
• D. Thermosphere

10. Biochemical oxygen demand (BOD) measures:

• A. Soil fertility
• B. Atmospheric oxygen
• C. Organic pollution in water
• D. Mineral content

11. Which is the hardest natural substance on Earth?

• A. Diamond
• B. Quartz
• C. Graphite
• D. Corundum

12. Which vegetation type is characterized by annual cycles of growth and dormancy?

• A. Evergreen forest
• B. Tropical rainforest
• C. Taiga
• D. Deciduous forest

13. Which term refers to the variety of life within an ecosystem?

• A. Genetic diversity
• B. Biodiversity
• C. Species richness
• D. Ecotone

14. The term 'eutrophication' refers to:

• A. Soil erosion
• B. Desertification
• C. Nutrient enrichment of water bodies
• D. Ozone depletion

15. Which agreement focuses on biodiversity conservation and sustainable use?

• A. Stockholm Convention
• B. RAMSAR Convention
• C. Kyoto Protocol
• D. Convention on Biological Diversity

16. Which process releases water vapor from plants into the atmosphere?

• A. Transpiration
• B. Evaporation
• C. Sublimation
• D. Condensation

17. Which biome is characterized by permafrost?

• A. Temperate forest
• B. Tundra
• C. Savanna
• D. Chaparral

18. Acid rain is primarily caused by emissions of:

• A. Carbon dioxide
• B. Methane
• C. Sulfur dioxide and nitrogen oxides
• D. Ozone

19. Which organism is a primary decomposer in forest ecosystems?

• A. Grass
• B. Deer
• C. Eagle
• D. Fungi

20. Which layer of soil is richest in organic matter?

• A. C-horizon
• B. O-horizon
• C. B-horizon
• D. R-horizon

21. Which ocean current affects India’s monsoon?

• A. Indian Ocean Dipole
• B. Gulf Stream
• C. Humboldt Current
• D. Labrador Current

22. Which crop is most affected by photochemical smog?

• A. Wheat
• B. Rice
• C. Pea
• D. Sugarcane

23. Which process converts dead organic matter into simpler compounds?

• A. Respiration
• B. Photosynthesis
• C. Transpiration
• D. Decomposition

24. Which endangered bird is found only in the Western Ghats?

• A. Great Hornbill
• B. Nilgiri Wood Pigeon
• C. Siberian Crane
• D. Kashmir Flycatcher

25. Which gas has the highest global warming potential?

• A. CO₂
• B. N₂O
• C. SF₆
• D. CH₄

26. Which reserve is known for conservation of olive ridley turtles?

• A. Gahirmatha Marine
• B. Gulf of Kutch
• C. Rani Jhansi Marine
• D. Malvan Marine

27. Which forest type is dominated by teak?

• A. Mangrove
• B. Tropical deciduous
• C. Alpine
• D. Evergreen

28. The Kyoto Protocol was adopted in the year:

• A. 1992
• B. 2005
• C. 1997
• D. 1997

29. Which is the topmost layer of the atmosphere?

• A. Stratosphere
• B. Mesosphere
• C. Thermosphere
• D. Troposphere

30. Which pollutant is monitored by Air Quality Index (AQI)?

• A. Particulate matter (PM₂.₅)
• B. Chlorofluorocarbons
• C. Helium
• D. Argon

31. Which crop rotation practice improves soil nitrogen?

• A. Wheat–rice
• B. Legume–cereal
• C. Cotton–soybean
• D. Sugarcane–maize

32. Which policy focuses on afforestation in India?

• A. Clean Air Programme
• B. National River Conservation Plan
• C. Green India Mission
• D. National Water Mission

33. Which term denotes the maximum population an environment can sustain?

• A. Niche
• B. Succession
• C. Habitat
• D. Carrying capacity

34. Which conservation strategy involves moving species to new habitats?

• A. Translocation
• B. In situ preservation
• C. Ex situ seed bank
• D. Wildlife corridor

35. Which biome covers most of central India?

• A. Tropical rainforest
• B. Tropical deciduous forest
• C. Desert
• D. Alpine

36. What does IPCC stand for?

• A. International Panel on Climate Change
• B. Intergovernmental Panel on Conservation
• C. Intergovernmental Panel on Climate Change
• D. International Programme on Climate Change

37. Which pollutant causes the greenhouse effect?

• A. Nitrogen
• B. Oxygen
• C. Argon
• D. Carbon dioxide

38. Which is a keystone species in many Indian forests?

• A. Tiger
• B. Rhino
• C. Elephant
• D. Deer

39. Which process fixes carbon into organic molecules?

• A. Respiration
• B. Photosynthesis
• C. Decomposition
• D. Fermentation

40. Which international agreement targets 1.5 °C warming?

• A. Kyoto Protocol
• B. Montreal Protocol
• C. Paris Agreement
• D. Stockholm Convention

41. Which water body is most affected by eutrophication in India?

• A. Chilika Lake
• B. Loktak Lake
• C. Dal Lake
• D. Vembanad Lake

42. Which insect is a major pollinator in ecosystems?

• A. Butterfly
• B. Bee
• C. Ant
• D. Cockroach

43. Which layer of rainforest receives the most sunlight?

• A. Understory
• B. Shrub layer
• C. Emergent layer
• D. Forest floor

44. Which process returns CO₂ to the atmosphere?

• A. Photosynthesis
• B. Transpiration
• C. Nitrogen fixation
• D. Respiration

45. What is the study of interactions among organisms and their environment?

• A. Ecology
• B. Biology
• C. Ethology
• D. Botany

46. Which renewable energy source converts sunlight to electricity?

• A. Biomass
• B. Geothermal
• C. Solar
• D. Tidal

47. Which soil conservation method involves plowing along contours?

• A. Crop rotation
• B. Contour plowing
• C. Terracing
• D. Intercropping

48. Which practice reduces methane emissions from rice fields?

• A. Alternate wetting and drying
• B. Continuous flooding
• C. Slash-and-burn
• D. Mono-cropping

49. Which phenomenon drives deep ocean currents?

• A. Wind
• B. Tides
• C. Surface temperature
• D. Thermohaline circulation

50. Which forest management practice involves selective tree removal?

• A. Clear-cutting
• B. Reforestation
• C. Silviculture
• D. Afforestation