Answer:
Your muscles are forced to work without enough oxygen. In these situations, your working muscles generate ATP anaerobically (i.e., without oxygen) using a process called fermentation. Fermentation is beneficial in that it can generate ATP quickly for working muscle cells when oxygen is scarce.
Explanation:
When oxygen is not present or if an organism is not able to undergo aerobic respiration, pyruvate will undergo a process called fermentation. Fermentation does not require oxygen and is therefore anaerobic. Fermentation will replenish NAD+ from the NADH + H+ produced in glycolysis.
