Fact 1: Feathers help birds fly and provide insulation.

Fact 2: Some birds are flightless birds.

Given the two facts above, answer the question "Why do the flightless have feathers?" with the following options: 
- layers of fat
 - Sublimation
 - it needs them
 - warm-blooded
 - Air conditioning
 - Radiation
 - Insulation
 - protect them


 

       Insulation  