The theory given in the science requires the proof. The experimental procedure and observation must be done to make any statements as the scientific theory.
The other scientists can ask question and make controversy about the particular scientific theory. This might occur when the theory affects the moral standards are blended with the phenomena of the nature. The controversy might also occur if its effects the ethics and against the laws of nature.
Aerobic respiration uses oxygen to produce ATP. Anaerobic respiration uses inorganic molecules to produce ATP. I hope that answered your question, my friend. :)
