Answer:
a
. Mixture
Explanation:
When solids, liquids and gases mix with one another, the product is usually a mixture.
Mixtures are classified as impure substances because:
- their composition is indefinite
- their constituents retains their identity
- constituents reacts differently to changed conditions
- they can easily be separated into constituents by physical methods
Pure substances are elements and compounds with typically definite compositions.
So, when substances in different phases combines, an heterogeneous mixture is produced.
