A solute dissolve in solvent is said to be a solution. It is homogeneous mixture that is the components of mixture are uniformly distributed throughout the mixture. The substance which is dissolved is solute whereas the substance in which the solute is dissolved is solvent. The solution can exist in any phase.
For example: Mixture of salt (solute) and water (solvent).
A mixture in which the components of mixture are not uniformly distributed throughout the mixture is known as heterogeneous mixture. The different materials of the mixture can be distinguished easily.
For example: Mixture of sand and water.