Oxygen
During aeroobic respiration oxigen reacts with sugar or glucose, producing carbon dioxide, water, and energy.
During anaerobic respiration when there is not enough oxygen, cells break down glucose into lactic acid and energy.
Pure chlorine is an example of an element.
An element is a chemical substance that cannot be broken down into simpler components in a chemical reaction or by any chemical means, and is made up of atoms that all have the same number of protons. Pure chlorine is an example of an element because it contains only one kind of an atom. Chlorine is a toxic, green, gaseous chemical element. Chlorine is a halogen, has an atomic number of 17, symbol Cl and is found in group 17 in the periodic table. Chlorine is highly reactive and a strong oxidizing and disinfecting agent.
Your answer would be C, the study of biogeography includes information about the location of fossils and living organisms
