Question

if a runner is doing vigorous exercise, which results from the anaerobic cellular process?
accumulation of lactic acid
accumulation of oxygen
depletion of ethanol
depletion of carbon dioxide

Explanation:

During vigorous exercise, when oxygen supply is limited, human cells undergo anaerobic respiration. In anaerobic respiration (lactic acid fermentation in humans), glucose is partially broken down. The end - product is lactic acid. Oxygen is consumed in cellular respiration (both aerobic and anaerobic pathways start with glycolysis which consumes some ATP - related to oxygen in a broader sense of energy production pathways, but it is not accumulated). Ethanol is a product of alcoholic fermentation (occurs in yeast, not in human muscle cells during exercise). Carbon dioxide is produced in aerobic respiration (when pyruvate is completely oxidized in the citric acid cycle) and in alcoholic fermentation (as yeast converts pyruvate to ethanol and \(CO_2\)), but in human anaerobic (lactic acid) fermentation, \(CO_2\) is not depleted.

Answer:

accumulation of lactic acid