Which process in the carbon cycle returns carbon dioxide to the atmosphere?

Which process in the carbon cycle returns carbon dioxide to the atmosphere?

• A. Photosynthesis
• B. Erosion
• C. Respiration
• D. Absorption by oceans

Answer: (C)

Respiration releases carbon dioxide back into the atmosphere. During cellular respiration, organisms break down glucose with oxygen to release energy, and carbon dioxide is produced as a waste product. This returns CO2 to the air and helps balance the amount taken up during photosynthesis, which uses CO2 to build sugars. Absorption by oceans removes CO2 from the atmosphere, so it doesn’t return it. Erosion affects rocks and carbon storage in the long term, but it isn’t a direct, immediate source of CO2 to the atmosphere.

Respiration releases carbon dioxide back into the atmosphere. During cellular respiration, organisms break down glucose with oxygen to release energy, and carbon dioxide is produced as a waste product. This returns CO2 to the air and helps balance the amount taken up during photosynthesis, which uses CO2 to build sugars. Absorption by oceans removes CO2 from the atmosphere, so it doesn’t return it. Erosion affects rocks and carbon storage in the long term, but it isn’t a direct, immediate source of CO2 to the atmosphere.