Approximately 60% of the mass of the human body is water.
(a)
Estimate the mass of water contained in the entire human population of the Earth. (Assume the number of people on the planet is 7 billion and the average mass of a human is 50 kg.)
2.1 ✕ 1010 kg
7.0 ✕ 109 kg
4.2 ✕ 109 kg
2.1 ✕ 1011 kg
3.5 ✕ 1011 kg