Environmental Biology — MCQs Biology 50 min Score: 0 Attempted: 0/50 Subscribe 1. Environmental biology primarily studies: (A) Structure of DNA only (B) Interactions of organisms with their environment (C) Human anatomy only (D) Chemical reactions in labs 2. Abiotic components of an ecosystem include: (A) Sunlight, water, temperature, and soil (B) Plants and animals only (C) Microbes only (D) Decomposers only 3. Biotic components include: (A) Soil and water only (B) All living organisms (C) Air only (D) Minerals only 4. Population in environmental biology refers to: (A) A group of individuals of the same species living in a habitat (B) All species in a habitat (C) Only plants (D) Only animals 5. Habitat is defined as: (A) Food chain (B) Group of species (C) Place where an organism lives (D) Energy flow 6. Niche refers to: (A) Only its population size (B) Only its habitat (C) Functional role of a species in an ecosystem (D) Only its diet 7. Producers are: (A) Autotrophs that produce organic compounds from sunlight (B) Herbivores only (C) Carnivores only (D) Decomposers only 8. Consumers include: (A) Water only (B) Plants only (C) Microbes only (D) Organisms that feed on other organisms 9. Decomposers are important because they: (A) Recycle nutrients back into the ecosystem (B) Produce sunlight (C) Consume water only (D) Absorb oxygen only 10. Primary consumers are: (A) Omnivores (B) Carnivores (C) Detritivores (D) Herbivores 11. Secondary consumers feed on: (A) Producers only (B) Primary consumers (C) Detritus only (D) Water only 12. Tertiary consumers feed on: (A) Microbes only (B) Producers only (C) Secondary consumers (D) Detritus only 13. Ecological pyramids represent: (A) Trophic structure and energy flow (B) DNA sequences only (C) Soil nutrients only (D) Temperature variations 14. Pyramid of numbers shows: (A) Nutrient cycling (B) Total biomass (C) Energy only (D) Number of organisms at each trophic level 15. Pyramid of biomass shows: (A) Number of species only (B) Total mass of organisms at each trophic level (C) Energy flow only (D) Water content only 16. Pyramid of energy shows: (A) Number of organisms only (B) Energy flow through trophic levels (C) Soil nutrients only (D) Water content only 17. Biogeochemical cycles describe: (A) Only photosynthesis (B) Movement of elements through biotic and abiotic components (C) Only respiration (D) Protein synthesis only 18. Carbon cycle involves: (A) Photosynthesis, respiration, and decomposition (B) Nitrogen fixation only (C) Sulfur cycle only (D) Water cycle only 19. Nitrogen fixation is carried out by: (A) Viruses only (B) Animals only (C) Fungi only (D) Rhizobium and cyanobacteria 20. Denitrification converts: (A) Nitrogen to ammonia only (B) Nitrates to nitrogen gas (C) Proteins to amino acids only (D) Oxygen to ozone 21. Phosphorus cycle does not include: (A) Soil and water (B) Atmospheric phase (C) Rock weathering (D) Decomposition 22. Oxygen is replenished in the environment by: (A) Respiration only (B) Photosynthesis (C) Combustion only (D) Decomposition only 23. Aquatic ecosystems include: (A) Grasslands only (B) Deserts only (C) Forests only (D) Freshwater and marine ecosystems 24. Freshwater ecosystems include: (A) Tundra only (B) Oceans only (C) Rivers, lakes, ponds, and wetlands (D) Deserts only 25. Marine ecosystems include: (A) Oceans, coral reefs, and estuaries (B) Lakes only (C) Rivers only (D) Grasslands only 26. Terrestrial ecosystems include: (A) Lakes only (B) Oceans only (C) Rivers only (D) Forests, deserts, grasslands, and tundra 27. Biomes are: (A) Ponds only (B) Large regions with similar climate, vegetation, and organisms (C) Desert patches only (D) Microorganisms only 28. Temperate forests are characterized by: (A) Deciduous trees and seasonal climate (B) Cacti and dry conditions (C) Mangroves only (D) Tundra vegetation 29. Desert ecosystems have: (A) Dense forests only (B) High rainfall only (C) Coral reefs only (D) Low rainfall and drought-resistant plants 30. Grasslands are dominated by: (A) Aquatic plants only (B) Trees only (C) Cacti only (D) Grasses and herbaceous plants 31. Tundra ecosystems are: (A) Humid tropical forests (B) Hot and dry (C) Cold, with permafrost and sparse vegetation (D) Desert only 32. Coral reefs are formed by: (A) Calcium carbonate secreting organisms (B) Trees only (C) Mangroves only (D) Cacti only 33. Keystone species are: (A) Microbes only (B) Species with no ecological role (C) Species with a large impact on ecosystem structure (D) Plants only 34. Invasive species are: (A) Native species only (B) Endangered species only (C) Non-native species that disrupt local ecosystems (D) Microbes only 35. Ecological succession is: (A) Soil formation only (B) Instant species replacement (C) Gradual change in species composition over time (D) Photosynthesis only 36. Primary succession occurs on: (A) Rivers only (B) Abandoned farmland only (C) Forest floors only (D) Bare land with no previous life 37. Secondary succession occurs on: (A) Deserts only (B) Newly formed rocks only (C) Oceans only (D) Previously inhabited land after disturbance 38. Climax community refers to: (A) Microbial colony only (B) Initial stage of succession (C) Temporary ecosystem (D) Stable, mature community at the end of succession 39. Biodiversity refers to: (A) Variety of life in all forms and levels (B) Only plant species (C) Only animal species (D) Only microbial species 40. Genetic diversity is: (A) Number of ecosystems (B) Variation in genes within a species (C) Species diversity only (D) Soil diversity only 41. Species diversity refers to: (A) Genetic variation only (B) Number of species in an area (C) Ecosystem types only (D) Soil microorganisms only 42. Ecosystem diversity refers to: (A) Variety of ecosystems in a region (B) Number of species only (C) Number of genes only (D) Microbial populations only 43. Endangered species are: (A) At risk of extinction (B) Abundant species (C) Keystone species only (D) Invasive species only 44. Conservation biology aims to: (A) Sequence DNA only (B) Produce antibiotics only (C) Ferment alcohol only (D) Preserve biodiversity and maintain ecosystem functions 45. Ecological footprint measures: (A) Biomass only (B) Energy in food chain only (C) Human impact on the environment (D) Soil nutrients only 46. Greenhouse gases include: (A) CO₂, CH₄, and N₂O (B) O₂ and N₂ only (C) H₂O only (D) NaCl only 47. Global warming is caused by: (A) Decomposition only (B) Photosynthesis only (C) Respiration only (D) Excess greenhouse gases 48. Acid rain is caused by: (A) SO₂ and NOₓ emissions (B) CO₂ only (C) O₂ only (D) Water only 49. Ozone layer depletion is due to: (A) CFCs and halons (B) CO₂ only (C) Oxygen only (D) Nitrogen only 50. Sustainable development aims to: (A) Focus only on agriculture (B) Exploit all natural resources (C) Focus only on industry (D) Meet current needs without compromising future resources