The main byproduct of aerobic respiration is carbon dioxide. This process occurs in cells where glucose is broken down in the presence of oxygen to produce energy in the form of ATP (adenosine triphosphate). Along with ATP, water and carbon dioxide are generated as waste products. The carbon dioxide is expelled from the organism, typically through the respiratory system in animals or released by plants during photosynthesis. The efficiency of aerobic respiration makes it a vital process for energy production in aerobic organisms.