Fact 1: Lungs are used for breathing air by land animals.

Fact 2: Mammals are animals with lungs, and they breath air.

Given the two facts above, answer the question "What do mammals breathe?" with the following options: 
- lung
 - Air
 - O2
 - Gas
 - Carbon dioxide
 - Urea
 - Heat
 - Moisture


 

  Air       