Which metabolic pathway generates energy without the use of oxygen?

The metabolic pathway that generates energy without the use of oxygen is anaerobic glycolysis. This process occurs in the cytoplasm of cells and involves the breakdown of glucose to produce ATP, the energy currency of the cell, while also generating lactic acid as a byproduct. Anaerobic glycolysis is particularly important during short bursts of high-intensity exercise, where the demand for energy exceeds the rate at which oxygen can be delivered to the muscle tissues.

In contrast, the oxidative system operates in the presence of oxygen to generate a larger amount of ATP through aerobic processes. Similarly, aerobic glycolysis also requires oxygen to efficiently convert glucose into energy. The creatine phosphate system provides a rapid source of energy for short-duration, high-intensity activities, but it relies on available phosphate stores and does not produce ATP through a breakdown of glucose. Therefore, while these other pathways may contribute to energy production, it is anaerobic glycolysis that specifically functions without oxygen, making it the correct answer.