CO2 is a byproduct of which biological process?

Carbon dioxide (CO2) is primarily produced as a byproduct of respiration, which is a metabolic process that occurs in living organisms. During respiration, cells convert glucose and oxygen into energy (ATP), releasing carbon dioxide and water as byproducts. This process is crucial for delivering energy required for various cellular functions and maintaining vital life processes.

In contrast, while other processes such as fermentation and digestion also involve the transformation of substances within an organism, they either produce different byproducts or operate under different conditions. For instance, fermentation, which can occur in anaerobic conditions, does produce carbon dioxide, but it is not the primary or main function like in respiration. Photosynthesis, on the other hand, consumes carbon dioxide rather than releasing it, as plants use CO2 along with sunlight to create glucose and oxygen. Therefore, respiration distinctly stands out as the biological process that consistently produces CO2 as a key byproduct.