6. Which of these is NOT a product of cellular respiration? * oxygen
O water
O ATP energy
O carbon dioxide

Explanation:

During aerobic cellular respiration, glucose reacts with oxygen, forming ATP that can be used by the cell. Carbon dioxide and water are created as byproducts. In cellular respiration, glucose and oxygen react to form ATP. Water and carbon dioxide are released as byproducts.

from khan academy

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.