Approximately what percentage of the body's weight is made up by water?

• A. 10-20 percent
• B. 30-40 percent
• C. 50-70 percent
• D. 80-90 percent

Answer: (C)

Water content is a major part of body weight, reflecting how essential water is for every cell and process in the body. In a typical adult, about 60% of body weight comes from water, though this can vary with age and body composition. Newborns have more water (around 75%), while as people age or gain fat, the percentage can drop to roughly 50–65%. Lean tissue has a higher water content than fat tissue, which is why men often have a slightly higher percentage than women. Most of the body’s water is inside cells, with the remainder outside cells in extracellular fluid like blood plasma and interstitial fluid. Because of this natural variation, an approximate range of 50–70% is the best way to capture how much of body weight is water.