Which process releases CO2 back into the atmosphere?

The process that releases CO2 back into the atmosphere is respiration. In respiration, organisms break down glucose molecules to obtain energy and, as a byproduct of this metabolic process, carbon dioxide is generated. This CO2 is then expelled from the organism and enters the atmosphere, contributing to the carbon cycle.

Photosynthesis, on the other hand, is the process by which plants convert sunlight into energy, using carbon dioxide and water to produce glucose and oxygen. Therefore, it actually removes CO2 from the atmosphere rather than releasing it.

Transpiration is the process by which water is absorbed by plant roots and released as water vapor through stomata in the leaves; while it involves water movement, it does not involve carbon dioxide. Condensation refers to the process where water vapor in the air cools and changes back into liquid, forming clouds or precipitation; this process is purely related to the water cycle and does not involve the release of CO2.

Thus, respiration is directly responsible for returning carbon dioxide to the atmosphere, facilitating this important aspect of the carbon cycle.