Final answer:
Water typically comprises 50 to 60 percent of body mass in adults, with the proportion varying based on factors such as age and body composition. The brain and kidneys have the highest water content, while teeth have the least.
Step-by-step explanation:
Depending upon body composition, water typically comprises 50 to 60 percent of body mass. This applies to adult men and women and reflects the fact that the percentage of body water changes with development, varying from higher percentages in infancy to lower percentages in old age. Notably, the brain and kidneys have the highest proportions of water, making up 80-85 percent of their masses, while teeth have the lowest, at 8-10 percent.
Additionally, water is a crucial component of both intracellular and extracellular fluids within the body. Intracellular fluid makes up about 50% of lean body weight, while extracellular fluids, including interstitial fluid and blood plasma, amount to roughly 20%. These fluids facilitate vital biological processes, such as cellular reactions and osmosis.