What percentage of the human body is water?

• A. 20%
• B. 40%
• C. 80%
• D. 60%

Answer: (C)

Water makes up a large part of the body because most tissues and fluids are water-based, and many essential processes occur in an aqueous environment. For the average adult, about 60% of body mass is water, with men typically around that value and women a bit lower due to higher body fat. Newborns, on the other hand, have much higher water content—roughly 75–80% of their body weight—which gradually decreases as they grow and body composition changes. So the 80% figure reflects newborns rather than adults; the key takeaway is that the exact percentage varies with age and body composition, with about 60% being a common ballpark for adults.