Final answer:
The statement that infants have approximately 40% of their body weight as water is false; they actually have about 75%. The percentage of body water content in humans decreases with age, with adults having approximately 50-60% of their body weight as water.
Step-by-step explanation:
The statement that infants have approximately 40% of their body weight as water is false. In fact, human beings are mostly water, with infants having about 75% of their body mass as water. This percentage of body water content is higher in infants compared to adults because the proportions of organs, muscles, fat, bone, and other tissues change as a person grows. The primary concept at play here is the distribution of intracellular and extracellular fluids in the body, which contribute to the total body water content.
These fluids are vital for bodily functions and are found at varying levels in different organs and tissues. For instance, the brain and kidneys have the highest proportions of water, ranging from 80-85% of their mass. The water content of the human body decreases with age, reaching about 50-60% in adults, and even lower, at around 45%, in old age. This highlights the importance of maintaining a proper balance of water and solutes within the body for normal functioning.