Fact 1: Mammals can also generate little bursts of heat by shivering.

Fact 2: Intense shivering and severe pain are natural body reflexes to cold water.

Given the two facts above, answer the question "Mammals can also generate little bursts of heat using natural body reflexes to what?" with the following options: 
- the environment
 - heating liquids
 - warm rooms
 - comfort
 - cold water
 - survive
 - Animal survival
 - tepid water


 

     cold water    