What process occurs in the absence of oxygen and results in the production of lactic acid in humans?

The process that occurs in the absence of oxygen and leads to the production of lactic acid in humans is anaerobic respiration. During this process, glucose is partially broken down to generate energy without the need for oxygen. The end product of this breakdown, when oxygen is limited, is lactic acid, which can accumulate in muscles and cause fatigue.

In anaerobic respiration, the pathway differs from aerobic respiration, which utilizes oxygen and produces carbon dioxide and water as byproducts along with a greater yield of energy. Photosynthesis, on the other hand, is the process used by plants to convert light energy into chemical energy and does not relate to energy production in humans. Cellular respiration encompasses both aerobic and anaerobic processes; however, it does not specifically refer to the absence of oxygen. Therefore, anaerobic respiration is the accurate term for the process that specifically results in lactic acid production in humans when oxygen is not available.