Which of the following best explains why humans need constant supplies of fresh water?
a. humans need a constant supply of water to provide them with essential vitamins.
b. humans need a constant supply of water to maintain proper hygiene.
c. constant supplies of freshwater are needed because body water is continually being lost.
d. constant supplies of freshwater are not actually necessary for survival.

The answer is C. The body needs constant supply of water because the water in the body is continually lost. On the average, our body contains approximately 60% of water and most of the water is inside the cells. however, this value varies depending on the age.  As we do our day to day activities, we lost water through sweating, urinating and by other means. Cells need water in order for them to live thus it is a must that we supply our body with water.