Birds are endothermic tetrapod vertebrates, and class Aves is for the birds, literally. Given these facts, what kind of animal would be an endothermic tetrapod vertebrate among the following options:
- animals in the class aves
 - barks and snarls
 - passenger pigeons
 - Something that is self-aware
 - Generating heat
 - retaining heat
 - absorb light energy
 - it keeps an organism warm


 

 animals in the class aves        