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, muscle cells undergo anaerobic respiration. In humans, this anaerobic process converts pyruvate into lactic acid. Oxygen is consumed, not accumulated. Ethanol is produced in anaerobic respiration in some microorganisms, not in human muscle - cells. Carbon dioxide is produced in aerobic respiration and some forms of anaerobic respiration in plants and microorganisms, but the main product of anaerobic respiration in human muscles is lactic acid.

Answer:

accumulation of lactic acid