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

Fact 2: Animals that survive develop an immunity, but are also carriers for life.

Given the two facts above, answer the question "what has a positive impact on an animal 's ability to be a carrier for life?" with the following options: 
- four limbs
 - staying frosty
 - staying isolated
 - prolactin release
 - staying warm
 - staying mad
 - coded genes
 - organic molecules


 

     staying warm    