Which nutrient can be used to produce energy in the absence of oxygen?

Answer;
Glucose
The nutrient that can be used to produce energy in the absence of oxygen is glucose.

Explanation;
Production of energy without using glucose is called anaerobic respiration. During this type of respiration less energy is released than the case of aerobic respiration. This is because the breakdown of glucose is incomplete. Anaerobic respiration produces an oxygen debt, which is the amount of oxygen needed to break lactic acid to carbon dioxide and water.