Which process increases atmospheric CO2 in the carbon cycle?

Which process increases atmospheric CO2 in the carbon cycle?

• A. Photosynthesis
• B. Respiration
• C. Condensation
• D. Evaporation

Answer: (B)

Respiration releases carbon dioxide back into the atmosphere as organisms convert stored organic matter into usable energy. In aerobic respiration, glucose reacts with oxygen to produce energy, with carbon dioxide and water as byproducts. That CO2 is returned to the air, increasing atmospheric CO2 levels. In the carbon cycle, photosynthesis pulls CO2 from the air to build sugars, while respiration reverses that process by releasing CO2. The other options involve processes that don’t directly alter atmospheric CO2: condensation and evaporation are water-cycle phase changes, and photosynthesis removes CO2 rather than adds to it.

Respiration releases carbon dioxide back into the atmosphere as organisms convert stored organic matter into usable energy. In aerobic respiration, glucose reacts with oxygen to produce energy, with carbon dioxide and water as byproducts. That CO2 is returned to the air, increasing atmospheric CO2 levels. In the carbon cycle, photosynthesis pulls CO2 from the air to build sugars, while respiration reverses that process by releasing CO2. The other options involve processes that don’t directly alter atmospheric CO2: condensation and evaporation are water-cycle phase changes, and photosynthesis removes CO2 rather than adds to it.