Where can the process of lactic-acid fermentation be found

Lactic fermentation is a minor process which occurs after glycolysis in anaerobic respiration. In it, an enzyme found in most every organism called lactate dehydrogenase catalyzes a reaction between the NADH produced from glycolysis with the pyruvate molecules to create the NAD+ necessary to begin glycolysis.

Explanation:

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%