Biosphere — MCQs

All questions with answers and explanations

Read the full set here, or use the practice card above to test yourself one question at a time.

1. The biosphere is best described as:

   • A single large ecosystem in Africa
   • The global sum of all ecosystems on Earth where life exists (correct answer)
   • Only the ozone layer
   • A synonym for atmosphere

   Explanation. The biosphere is the global sum of all ecosystems on Earth — the zone where the lithosphere, hydrosphere, and atmosphere overlap and support life.

2. A biome is best defined as:

   • A single pond ecosystem
   • A large geographical region defined by climate and its characteristic plant/animal life (correct answer)
   • A synonym for biosphere
   • A protected area declared by the government

   Explanation. A biome is a large, climate-defined geographical region with its own characteristic plant and animal communities — much larger in scale than a single ecosystem.

3. Which of the following is an example of a terrestrial biome?

   • Estuary
   • Marine biome
   • Savanna (correct answer)
   • Freshwater biome

   Explanation. Savanna is a terrestrial biome. Estuaries, marine biomes, and freshwater biomes are all aquatic biomes.

4. The Sundarbans is a well-known example of which kind of aquatic biome?

   • Marine biome
   • Estuary (correct answer)
   • Tundra
   • Taiga

   Explanation. The Sundarbans is an estuary — a transitional zone where freshwater from rivers mixes with saltwater from the sea, home to mangrove forests.

5. A 'Biosphere Reserve' in Indian conservation policy is primarily designed to protect:

   • Only a single endangered species
   • Only mineral resources
   • Overall biosphere function, including whole-ecosystem health and human-environment relationships (correct answer)
   • Only urban green spaces

   Explanation. Biosphere Reserves are designed to preserve representative biosphere function as a whole — not just a single species or habitat in isolation.

6. Which biome is characterised by cold winters, mild summers, and coniferous trees such as pine and spruce?

   • Tundra
   • Taiga (Boreal Forest) (correct answer)
   • Savanna
   • Tropical Rainforest

   Explanation. Taiga (Boreal Forest) is defined by cold winters, mild summers, and coniferous trees like pine, spruce, and fir.

7. Compared to an ecosystem, a biome is:

   • Always smaller in scale
   • Exactly the same scale
   • Much larger in scale, often spanning continents (correct answer)
   • Not related in scale at all

   Explanation. A biome is a much larger scale of ecological classification than an ecosystem — an ecosystem can be as small as a pond, while a biome can span continents.

8. Which of the following is NOT a common threat to biomes?

   • Deforestation
   • Climate change
   • Overexploitation
   • Increased genetic diversity (correct answer)

   Explanation. Increased genetic diversity is a conservation benefit, not a threat. The common threats are deforestation, climate change, pollution, overuse and loss of habitat.