Answer: c) mixture.
Explanation:
An atom is the smallest entity of any substance which consists of subatomic particles called as neutrons, protons and electrons.
An element is a pure substance which is composed of atoms of similar elements. Example: [tex]H_2[/tex]
Mixture is formed when atoms of similar or different elements are mixed in no fixed ratio without any chemical combination.
A compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass. Example: [tex]H_2O[/tex]
