Fact 1: Staying warm has a positive impact on an animal 's survival.

Fact 2: Proper hydration is necessary to stay warm.

Given the two facts above, answer the question "what is required for survival?" with the following options: 
- sugar
 - soil
 - Energy.
 - nitrogen
 - hormones
 - hydration
 - energy
 - evaporation


 

      hydration   