14) Air can be considered a mixture. Which statement helps describe air?
A)Air contains a fixed ratio of atoms.
B)The components of air separate into visible layers.
C)The components of air can be separated by chemical means.
D)The exact mixture of components varies from point to point.

the components of air can be separated by chemical means

D)  The exact mixture of components varies from point to point.

Explanation:

Here's why: Air can be considered a homogeneous mixture.The exact mixture of components varies from point to point. Air is made up of individual elements and compounds. When near a cow pasture, you can smell the compounds associated with cow patties but you can not see these as separate from the rest of the air

the answer is definitely c.