Here's why:

* Solutions can have different states: A solution is a homogeneous mixture, meaning the components are evenly distributed. This can occur in various combinations of states:

* Liquid solutions: The most common type, where a solid, liquid, or gas dissolves in a liquid solvent. (e.g., sugar in water, salt in water, carbon dioxide in soda)

* Solid solutions: One solid dissolves in another solid. (e.g., brass, which is a mixture of copper and zinc)

* Gaseous solutions: One gas dissolves in another gas. (e.g., air, which is a mixture of nitrogen, oxygen, and other gases)

In summary: While many solutions involve a liquid solvent, the solute can be a solid, liquid, or gas. The key is that the components are evenly distributed throughout the mixture, regardless of their initial states.