How does water function in the body?

Water plays a crucial role in the human body, comprising about 60% to 70% of total body weight. This high percentage reflects its vital contributions to several physiological functions, including maintaining hydration, facilitating biochemical reactions, and supporting cellular structure. Water acts as a solvent for nutrients, aids in digestion, and enables the transport of oxygen and nutrients to cells while also removing waste products.

The fact that water makes up such a significant portion of the body emphasizes its importance in overall health and bodily functions—not only does it help in maintaining homeostasis, but it also supports other elements such as muscle contraction and joint lubrication. Hydration levels significantly affect performance, metabolism, and even mood.

In contrast, the other options do not accurately represent the essential roles of water. While energy is necessary for bodily functions, it is derived from nutrients rather than water itself. Water provides structure and support for muscles but is not the primary structural component. Similarly, while water does help regulate body temperature through processes like sweating, its functions in the body extend far beyond just temperature regulation.