What is the source of the majority of the energy needed by muscles for physical activity that continues for longer than 30 or 40 minutes? A. ATP stored in muscle fi bres. B. glycolysis of glucose in the cell cytoplasm C. ATP produced from creatine phosphate stored in muscle fi bres D. aerobic respiration of pyruvic acid in mitochondria
Option D. Aerobic repiration of pyruvic acid in mitochondria is the source of the majority of the energy needed by muscles for physical activity.
