A solute and a solvent that do not separate is called a homogeneous mixture or a solution.

Here's why:

* Homogeneous mixture: This means the mixture has a uniform composition throughout. You can't distinguish between the solute and solvent particles visually or by other simple means.

* Solution: This is a specific type of homogeneous mixture where one substance (the solute) is dissolved completely into another (the solvent).

Examples:

* Saltwater: Salt (solute) dissolves completely in water (solvent), forming a homogeneous mixture.

* Sugar in coffee: Sugar (solute) dissolves in coffee (solvent), creating a solution.

* Air: Gases like nitrogen and oxygen are evenly mixed, forming a homogeneous mixture.

Let me know if you have any other questions!