Energy flow and nutrient cycles MCQs

1. What is the primary source of energy for most ecosystems?

(A) Geothermal heat

(B) Fossil fuels

(C) Wind energy

(D) The Sun

2. Which process do plants use to convert solar energy into chemical energy?

(A) Respiration

(B) Photosynthesis

(C) Transpiration

(D) Decomposition

3. In an ecosystem, what percentage of energy is typically transferred from one trophic level to the next?

(A) 10%

(B) 50%

(C) 100%

(D) 1%

4. What is the role of primary consumers in an ecosystem?

(A) To break down dead organic matter

(B) To consume producers

(C) To capture solar energy

(D) To eat secondary consumers

5. Which nutrient cycle involves the process of nitrogen fixation?

(A) Carbon cycle

(B) Water cycle

(C) Phosphorus cycle

(D) Nitrogen cycle

6. What is the process by which water vapor returns to Earth’s surface as precipitation?

(A) Evaporation

(B) Condensation

(C) Precipitation

(D) Transpiration

7. Which of the following best describes a decomposer’s role in nutrient cycling?

(A) Converting carbon dioxide to oxygen

(B) Consuming primary consumers

(C) Producing energy through photosynthesis

(D) Breaking down dead organisms and releasing nutrients back into the soil

8. In the carbon cycle, how is carbon released back into the atmosphere?

(A) Through photosynthesis

(B) By nitrogen fixation

(C) By the respiration of animals and plants

(D) Through the absorption by oceans

9. What term describes the continuous movement of water on, above, and below the surface of the Earth?

(A) Carbon cycle

(B) Nitrogen cycle

(C) Hydrologic cycle

(D) Phosphorus cycle

10. In which part of the nutrient cycle do plants absorb nutrients from the soil?

(A) Decomposition

(B) Photosynthesis

(C) Assimilation

(D) Nitrogen fixation