* Both solutions and substances are matter.

* Both solutions and substances can be composed of more than one element.

* Both solutions and substances can exist in different states of matter (solid, liquid, or gas).

* Both solutions and substances can be classified as either pure or impure.

* Both solutions and substances can undergo physical changes, such as changes in temperature or pressure.

Differences:

* A substance is a pure compound, while a solution is a mixture of two or more substances.

* The composition of a substance is always the same, while the composition of a solution can vary.

* Substances have definite melting points and boiling points, while solutions have variable melting points and boiling points.

* Substances are not easily separated into their components, while solutions can be easily separated into their components.

* Substances are typically solids, while solutions can be solids, liquids, or gases.