And to state the obvious:
1) While life has existed for 3.7 billion years, humans have existed for only 400,000.
2) Many life-forms consume less water than a human and some none at all.
3) The global human population reached 6 billion in 1999 AD. Not 38,000 BC.
4) The vast majority of water consumed by humans is returned to their environment in a matter of days via sweating, urination and expiration. The remaining amount is returned upon decomposition following death.
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