Final answer:
Carbon dioxide is produced during the Krebs cycle and the electron transport chain stages of cellular respiration, and it is then exhaled.
Step-by-step explanation:
The two stages of cellular respiration that produce the carbon dioxide you exhale are the Krebs cycle and the electron transport chain. During the Krebs cycle, which takes place in the matrix of the mitochondria, pyruvate from glycolysis is further broken down and carbon dioxide is released as a waste product. Then, in the electron transport chain, more carbon dioxide is produced alongside water and adenosine triphosphate (ATP), which is used as energy by the cell.