Fact 1: Most people can survive only a few days without water.

Fact 2: Water is made up of H2O molecules.

Given the two facts above, answer the question "What is something people can survive only a few days without?" with the following options: 
- Shelter
 - Food
 - O3
 - NaCl
 - urea
 - H20
 - H2O
 - Salt


 

       H2O  