How much of a muscle's composition is water?

Muscle tissue is composed of approximately 75 percent water. This high water content is essential for various physiological functions, including nutrient transport, waste removal, temperature regulation, and maintaining the structure and integrity of muscle cells. The presence of water contributes to the muscle's flexibility and its ability to contract effectively during physical activity. Thus, the correct choice reflects a significant understanding of muscle composition and its vital role in exercise and overall health.