Answer the following question given this paragraph: 

Most nonmetals are poor conductors of heat. In fact, they are such poor conductors of heat that they are often used for insulation. For example, the down filling in this sleeping bag is full of air, which consists primarily of the nonmetal gases oxygen and nitrogen. These gases prevent body heat from escaping to the cold outside air.


Q: What are the three most common elements in the air we breathe?

 Choices:

- oxygen, nitrogen, H20

- nitrogen, argon, hydrogen

- argon, oxygen, hydrogen

- nitrogen, oxygen and argon

A:
nitrogen, oxygen and argon
