What does oxygen allow humans to do?
C is the correct answer. Humans can not produce food, only autotrophs can. Those organisms don’t use oxygen to produce food, but CO2 and H2O. Humans do not need oxygen to digest food on the organism level. That is done through enzymes and acid in the alimentary canal. Oxygen is not needed to breath. It may be hard to understand, but breathing only requires muscle contractions, which requires ATP. The answer is produce ATP because without oxygen, there is nothing to accept the H+ ions (protons) after they run through the ATP synthase protein. Oxygen is an electron acceptor, and kind of catches the H+ ions as they fall through the ATP synthase. Without the oxygen there to reduce the H+, there would be no ATP production.
