Problem:
Quite simply, some organisms metabolize glucose under anaerobic conditions via Glucose->(2) Pyruvic Acid->(2)Ethyl Alcohol. Some organisms, however, metabolize to lactic acid.
Question 1: When did such a process (lactic acid) arise biochemically from its related (ethanol) fermentation?
Question 2: how was it selected for?
Question 3: What were the advantages?
Please explain all the advantages.