A mixture with medium sized particles that do not settle out is called

Answer: colloid

Explanation:

Colloids are solutions in which small sized particles are suspended throughout the solution as they do not settle own their own. Colloids are defined as the mixtures where the size of the particle is within the range of 2nm to 1000 nm. In these mixtures, physical boundary is seen between the dispersed phase and dispersed medium.

Colloids are solutions with particle size intermediate between true solutions and suspensions. Suspensions have large sized particles which settle when left undisturbed for sometime and thus can be filtered off easily. The particle size in colloids is less and hence they do not settle under the effect of gravity.