Fact 1: Birds are endothermic tetrapod vertebrates.

Fact 2: Legs define Tetrapods.

Given the two facts above, answer the question "What are endothermic vertebrates with legs?" with the following options: 
- Birds
 - mammals
 - Snakes
 - ducks
 - Lizards
 - ants
 - long
 - toads


 

 Birds        