A colloid is a heterogeneous mixture whose particles are not as small as solution but they are so small that cannot be seen by naked eye.Mixtures can be homogeneous or heterogeneous. A colloid is a mixture where very small particles of one substance are evenly distributed throughout another substance. They appear very similar to solutions, but the particles are suspended in the solution rather than fully dissolved.
Homogenized milk is a colloid because it contains large particles such as fats and proteins that do not settle out of solution. If the milk is not homogenized, it is a heterogeneous mixture because the different components will separateMilk is a colloidal suspension and it is a kind of heterogeneous mixture in which particles are suspended in a second substance but do not fall out of mixture.