Question

the air we breathe is a(n) ____.
○ compound
○ mixture
○ element
○ alloy

Explanation:

Air is composed of various gases like nitrogen, oxygen, carbon dioxide, etc., mixed together without a fixed chemical formula, so it's a mixture. A compound has a fixed composition and chemical formula, an element is a pure substance with one type of atom, and an alloy is a mixture of metals (or metal and non - metal) in solid form.

Answer:

B. mixture