When experiencing oxygen debt why do human cells not carry out the process of alcohol fermentation?

Whenever, there is lack of oxygen with in the body, lactic acid and alcoholic fermentation starts within the cells. This usually happens when the body is lack of energy (a condition at the time of extreme body exercise).

In the alcoholic fermentation, carbon dioxide and alcohol is formed from the pyruvic acid. In this process, ATP is formed from the continuously even after low oxygen through glycolysis and NAD+ also forms from NADH. Also the ethanol is generated by alcoholic fermentation.

In the  non-fermentation respiration processes electron transport chains uses more energy from pyruvate.Usually, the aerobic respiration consumes oxygen as the final electron acceptor as compared to the non-fermentation anaerobic respiration which use inorganic electron acceptors sources.

In t he fermentation process,  pyruvate is transformed into  other molecules such as  lactate / ethanol so that glycolysis just be in continuation with the production of  NAD⁺ . In this process energy is only consumed and no additional energy generated.  Thus, while experiencing oxygen debt, human cells do not carry out the process of alcohol fermentation

name and explain one of the event that occurs during meiosis that increases the variation in offspring even more than simple reproduction?