You are presented with the question "What is a fiber that is not found in reptiles or birds?" and the following answer choices: 
- Tail
 - muscle
 - feathers
 - sugar
 - down
 - hair
 - Fat
 - scales

Now knowing that hair is a fiber that is found only in mammals and animals can be classified into mammals, reptiles, birds, choose the best answer.


 

      hair   