Fact 1: An egg requires warmth to survive.

Fact 2: Sunlight and warmth are vital to the incubation of eggs and a successful hatch of fry.

Given the two facts above, answer the question "An egg requires _ to survive" with the following options: 
- incubation
 - condensation
 - Energy.
 - heat energy
 - nutrients
 - energy
 - moisture
 - oxygen


 

 incubation        