Which of the following is a key part of the carbon cycle?

• A. Return of CO₂ to the atmosphere by burning fossil fuels
• B. Assimilation of atmospheric CO₂ by plant photosynthesis
• C. Return of CO₂ to the atmosphere by animal and plant respiration
• D. Breakdown by decomposers of carbon-containing dead plants and animals
• E. All of the listed responses are correct.

Answer: (E)

Verified step by step guidance

1. Understand the carbon cycle: The carbon cycle is a series of processes by which carbon compounds are interconverted in the environment, involving the incorporation of carbon dioxide into living tissue by photosynthesis and its return to the atmosphere through respiration, the decay of dead organisms, and the burning of fossil fuels.
2. Consider the role of photosynthesis: Plants assimilate atmospheric CO2 during photosynthesis, converting it into glucose and other organic compounds. This process is crucial for the carbon cycle as it removes CO2 from the atmosphere.
3. Examine respiration: Both plants and animals return CO2 to the atmosphere through respiration. This process involves breaking down glucose for energy, releasing CO2 as a byproduct.
4. Analyze decomposition: Decomposers, such as bacteria and fungi, break down dead plants and animals, releasing carbon back into the environment. This process contributes to the cycling of carbon.
5. Evaluate the impact of burning fossil fuels: Burning fossil fuels releases stored carbon in the form of CO2 back into the atmosphere, significantly impacting the carbon cycle and contributing to climate change.