What processes return carbon to the atmosphere from living organisms?

What processes return carbon to the atmosphere from living organisms?

• A. Photosynthesis
• B. Respiration
• C. Transpiration
• D. Combustion

Answer: (B)

Carbon returns to the atmosphere through respiration. In respiration, cells break down sugars to release energy, and the carbon atoms in those sugars are released as carbon dioxide. This CO2 is then exhaled or expelled, cycling back into the air. This is the opposite of photosynthesis, which pulls CO2 from the atmosphere to build organic matter. Transpiration is about water loss and doesn’t involve carbon movement. Combustion releases CO2 when organic material is burned, but it’s a chemical burning process, not a living metabolic one, so the primary process by living organisms is respiration.

Carbon returns to the atmosphere through respiration. In respiration, cells break down sugars to release energy, and the carbon atoms in those sugars are released as carbon dioxide. This CO2 is then exhaled or expelled, cycling back into the air. This is the opposite of photosynthesis, which pulls CO2 from the atmosphere to build organic matter. Transpiration is about water loss and doesn’t involve carbon movement. Combustion releases CO2 when organic material is burned, but it’s a chemical burning process, not a living metabolic one, so the primary process by living organisms is respiration.