Name the two process that play …

Respiration: All living species, from a single bacteria, plants, and animals use oxygen for breathing. It is the metabolic processes in which we inhale oxygen and exhale carbon dioxide.
Decomposition: One of the important steps in oxygen cycle is decomposition in which when an animal dies, it decomposes and it uses all the oxygen and releases carbon dioxide. Oxygen is also used up in rusting as oxidation takes place here.
Combustion: It is also one of the most important processes which are just like burning for which oxygen, fuel, and heat is required. There can be no fire without oxygen and when anything burns it uses the oxygen and replaces it with carbon dioxide in case of hydrocarbons.
Formation of oxides: This process also requires oxygen. It is the formation of oxides which is also called oxidation. Rusting is the best example of oxidation.  In this process, metals like iron or alloy rust when they are exposed to moisture and oxygen for a long period of time. New compounds of oxides are formed by the combination of oxygen with the metal.