What substance makes up approximately 1/2 to 1/3 of the human body?

Water makes up approximately 1/2 to 1/3 of the human body, which is crucial for various physiological processes. It serves as a solvent for biochemical reactions, regulates body temperature, facilitates digestion, and helps transport nutrients and waste. In adults, water typically constitutes about 60% of body weight, while in infants, it can account for up to 75%. This high percentage emphasizes the fundamental role water plays in maintaining homeostasis in the body.

While proteins, fats, and minerals are vital components of the body and contribute to various functions such as building tissues, providing energy, and supporting metabolic processes, they do not make up as significant a portion of body composition compared to water. Understanding the importance of water can also highlight the need for proper hydration for overall health.