Oxygen does not have just one use.
For oxygen masks for firefighters, scuba divers etc
One gas is oxygen
An anaerobic function is one that does not use oxygen.
One could ask their friends if they have some information about oxygen bars. If one is interested in the effects of inhaling increased levels of oxygen, one could go to the library and look for books about the medical use of oxygen.
Aerobic organisms use oxygen.
To carry oxygen and carbon dioxide through the blood stream.
What do you mean? To test for oxygen being produced, light a splint, blow it out then put it over the object you beleve is producing oxygen and if the splint re-lights oxygen is being produced.
One way to test for the presence of oxygen gas is to use a glowing splint test. If the gas is oxygen, the glowing splint will relight when introduced into the gas due to oxygen's ability to support combustion.
The fact that it does not use oxygen is precisely why it is anaerobic. Anaerobic means without oxygen. If it did use oxygen, it'll be called aerobic.
Fishes use Oxygen in water. They absorb the absorbed oxygen through their gills.
Plants produce Oxygen after the completion of photosynthesis glucose and oxygen are the final products