Answer:
The carbon dioxide breathed out is a by-product of the process of cell respiration, as is water. In this process, energy is produced in the mitochondria of cells. ... When that reacts with oxygen (O2) in the cells, it produces carbon dioxide (CO2) and water (H2O). C6H12O6 plus 6O2 gives 6CO2 plus 6H2O plus energy.
