Final answer:
The process of lactic acid fermentation in muscle cells during low oxygen conditions is known as anaerobic respiration (option A). It allows for the continued production of ATP via glycolysis, using pyruvate and NADH to generate lactic acid and NAD+, which is necessary for the ongoing energy needs of muscle cells during intense exercise.
Step-by-step explanation:
Fermentation leading to the excretion of lactate in muscle cells is a form of anaerobic respiration. This biochemical process happens when oxygen is scarce, and cells like muscle cells need energy. During intense exercise, muscles consume ATP at a rate that oxygen delivery can't match, leading to lactic acid fermentation.
The overall reaction for lactic acid fermentation is: pyruvic acid + NADH → lactic acid + NAD+. Lactic acid then accumulates in muscle cells and is transported to the liver, where it can be converted back into pyruvate or glucose via the Cori cycle. While fermentation doesn't yield as much ATP as aerobic respiration, it allows for continuous production of ATP via glycolysis, which is critical during short bursts of high-intensity activity.