During aerobic respiration. #H_2O# is formed. Where does the oxygen atom for the formation of the water come from?
The oxygen was found in one of the reactants of the process, but we cannot state for certain which compound.
All that can be said is that this oxygen atom was originally one of the atoms in the reactants of the process (the
So, it was either part of the food that was consumed to produce the glucose, or the oxygen that was transported from the lungs via the blood to the cell. But which one? Impossible to say. One