Q1. Which ofthe following is NOT a component of an ecosystem?
(a) Producers
(b) Decomposers
(c) Abiotic factors
(d) Geological time scale
Answer: (d)
Explanation: An ecosystem consists of biotic components (producers, consumers, decomposers) and abiotic factors (soil, water, climate). Geological time scale is a concept of Earth’s history, not a component of a functioning ecosystem.
Q2. The term “biodiversity hotspot” was popularized by which scientist?
(a) Norman Myers
(b) Rachel Carson
(c) E.O. Wilson
(d) Jane Goodall
Answer: (a) Explanation: Norman Myers introduced the concept of biodiversity hotspots in 1988 to identify regions with exceptional concentrations of endemic species facing high habitat loss.
Q3. Which gas is primarily responsible for the greenhouse effect on Earth?
(a) Oxygen (O₂)
(b) Nitrogen (N₂)
(c) Carbon dioxide (CO₂)
(d) Argon (Ar)
Answer: (c)
Explanation: Carbon dioxide traps infrared radiation emitted from Earth’s surface, contributing significantly to the greenhouse effect and global warming.
Q4. The “Red Data Book” published by IUCN contains information about:
(a) Endangered medicinal plants only
(b) Threatened species of flora and fauna
(c) All known microbes
(d) Fossil records
Answer: (b)
Explanation: The IUCN Red List (often called the Red Data Book) assesses the extinction risk of species worldwide, covering both plants and animals.
Q5. Which of the following biogeochemical cycles involves the conversion of atmospheric nitrogen into ammonia by nitrogen‑fixing bacteria?
(a) Carbon cycle
(b) Phosphorus cycle
(c) Nitrogen cycle
(d) Sulphur cycle
Answer: (c) Explanation: In the nitrogen cycle, bacteria such as Rhizobium and Azotobacter convert N₂ gas into ammonia (NH₃) through nitrogen fixation.
Q6. The Ramsar Convention is related to the conservation of: (a) Tropical rainforests
(b) Wetlands of international importance
(c) Coral reefs
(d) Desert ecosystems
Answer: (b)
Explanation: The Ramsar Convention, adopted in 1971, aims to conserve and wisely use wetlands designated as sites of international importance.
Q7. Which Indian law provides for the protection and improvement of the environment and prevention of hazards to human beings, other living creatures, plants, and property?
(a) Wildlife Protection Act, 1972
(b) Forest Conservation Act, 1980
(c) Environment (Protection) Act, 1986
(d) Biological Diversity Act, 2002
Answer: (c)
Explanation: The Environment (Protection) Act, 1986 is an umbrella legislation empowering the central government to take measures to protect and improve environmental quality.
Q8. “Ecological succession” refers to:
(a) The seasonal migration of birds
(b) The gradual change in species composition of a community over time (c) The increase in population size of a single species
(d) The cycling of nutrients in soil
Answer: (b) Explanation: Succession is the process by which the structure of a biological community evolves over time, progressing from pioneer species to a stable climax community.
Q9. Which of the following is a characteristic of an r‑selected species?
(a) Long lifespan, few offspring, high parental care
(b) Short lifespan, many offspring, little parental care
(c) Large body size, low reproductive rate
(d) Specialized niche, high competitive ability
Answer: (b)
Explanation: r‑selected species thrive in unstable environments, producing many offspring quickly with minimal investment per offspring.
Q10. The “Montreal Protocol” primarily aims to phase out substances that deplete:
(a) Greenhouse gases
(b) Ozone layer
(c) Oceanic plastics
(d) Soil fertility
Answer: (b)
Explanation: Adopted in 1987, the Montreal Protocol targets chlorofluorocarbons (CFCs) and other ozone‑depleting substances to protect the stratospheric ozone layer.
Q11. Which of the following is NOT a greenhouse gas?
(a) Methane (CH₄)
(b) Nitrous oxide (N₂O) (c) Water vapour (H₂O) (d) Neon (Ne)
Answer: (d)
Explanation: Neon is a noble gas present in trace amounts and does not absorb infrared radiation; it is not considered a greenhouse gas.
Q12. “Keystone species” are important because they:
(a) Have the highest biomass in an ecosystem
(b) Disproportionately affect the structure and function of their community
(c) Are always apex predators
(d) Are endemic to a single location
Answer: (b)
Explanation: Removal of a keystone species leads to significant changes in community composition and ecosystem processes, despite its relatively low abundance.
Q13. The term “ecotone” refers to: (a) A zone of transition between two adjacent ecological systems
(b) The innermost part of a forest
(c) A protected area with no human activity
(d) A laboratory simulation of climate change
Answer: (a)
Explanation: An ecotone is a boundary area where two communities meet and integrate, often exhibiting higher biodiversity than the adjacent zones.
Q14. Which Indian state has the largest area under forest cover as per the India State of Forest Report 2021?
(a) Madhya Pradesh
(b) Arunachal Pradesh
(c) Chhattisgarh (d) Maharashtra
Answer: (a)
Explanation: Madhya Pradesh consistently tops the list with the largest recorded forest area in India.
Q15. The “CITES” convention regulates:
(a) Trade in endangered species of wild fauna and flora
(b) Emission of industrial pollutants
(c) Use of genetically modified organisms
(d) Management of marine fisheries
Answer: (a)
Explanation: The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) aims to ensure that international trade does not threaten species’ survival.
Q16. Which of the following processes is responsible for the formation of acid rain?
(a) Evaporation of seawater
(b) Oxidation of sulfur dioxide and nitrogen oxides in the atmosphere (c) Photosynthesis in aquatic plants
(d) Decomposition of organic matter in soils
Answer: (b)
Explanation: SO₂ and NOₓ emitted from fossil fuel combustion react with water, oxygen, and other chemicals to form sulfuric and nitric acids, which fall as acid rain.
Q17. The “Western Ghats” and “Eastern Himalayas” are recognized as:
(a) Biosphere reserves only
(b) Biodiversity hotspots
(c) World Heritage Sites only
(d) Ramsar sites
Answer: (b)
Explanation: Both regions meet the criteria for biodiversity hotspots: high endemic plant species loss and significant habitat degradation.
Q18. “Biomagnification” refers to:
(a) Increase in population size of a species over generations
(b) Increase in concentration of a toxin as it moves up trophic levels
(c) Enhancement of soil fertility through organic matter addition
(d) Expansion of a species’ geographical range
Answer: (b)
Explanation: Persistent, lipid‑soluble pollutants (e.g., DDT, mercury) become more concentrated in organisms at higher trophic levels, posing greater risk to top predators.
Q19. Which of the following is an example of an ex‑situ conservation method?
(a) National parks
(b) Wildlife sanctuaries
(c) Seed banks
(d) Community reserves
Answer: (c)
Explanation: Ex‑situ conservation involves preserving components of biodiversity outside their natural habitats, such as in seed banks, botanical gardens, or zoos.
Q20. The “Nitrogen‑fixing” ability of legumes is due to a symbiotic relationship with:
(a) Mycorrhizal fungi (b) Rhizobium bacteria
(c) Cyanobacteria in leaf nodules
(d) Actinobacteria in soil
Answer: (b)
Explanation: Legume roots form nodules that house Rhizobium bacteria, which convert atmospheric N₂ into ammonia usable by the plant.
Q21. Which gas is the most abundant in Earth’s atmosphere?
(a) Oxygen
(b) Carbon dioxide
(c) Nitrogen
(d) Argon Answer: (c)
Explanation: Nitrogen makes up about 78% of the atmosphere by volume, followed by oxygen (~21%) and argon (~0.9%).
Q22. The concept of “carrying capacity” in ecology denotes:
(a) The maximum rate of photosynthesis in a plant
(b) The maximum number of individuals of a species that an environment can sustain indefinitely
(c) The total biomass of predators in a food web
(d) The speed at which nutrients cycle in an ecosystem Answer: (b)
Explanation: Carrying capacity (K) is the population size that the environment can support given its resources, beyond which growth slows or declines.
Q23. Which of the following is a primary pollutant?
(a) Ozone (O₃) formed in the troposphere
(b) Sulphur dioxide (SO₂) emitted from factories
(c) Acid rain
(d) Smog
Answer: (b)
Explanation: Primary pollutants are directly emitted from sources (e.g., SO₂ from coal combustion). Ozone and smog are secondary pollutants formed by chemical reactions in the atmosphere.
Q24. The “Nagoya Protocol” is related to:
(a) Climate change mitigation (b) Access to genetic resources and fair sharing of benefits
(c) Protection of migratory birds (d) Regulation of ocean dumping
Answer: (b)
Explanation: Adopted in 2010 as a supplementary agreement to the Convention on Biological Diversity, the Nagoya Protocol addresses access to genetic resources and benefit‑sharing.
Q25. Which of the following statements about ecological pyramids is correct?
(a) Pyramids of number are always upright.
(b) Pyramids of biomass can be inverted in aquatic ecosystems.
(c) Pyramids of energy show a gain of energy at higher trophic levels.
(d) Pyramids of energy can be inverted.
Answer: (b)
Explanation: In some aquatic ecosystems, phytoplankton have high turnover but low standing biomass, leading to an inverted biomass pyramid, whereas energy pyramids are always upright due to the 10% rule.
