Answer:
The two reasons are listed below.
Step-by-step explanation:
Humans AND animals need CLEAN drinking water because water is the life-blood for most if not all organisms, and keeps them alive.
Humans AND animals need CLEAN drinking water because, without it, they will die. Yes, food may keep you alive, but you can only survive so long without water (about a week). While you can survive for a very long time without food (about a month, depends on your weight).