It is a solution in which a material is evenly suspended in a liquid.
they are very useful in medical field ...
hey can be used to manipulate blood conditions. 
hope it helped
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The solution in which the particles easily scatter a beam of visible light is known as colloidal solution.In this the particles are suspended.This is a type of heterogeneous mixture. Colloidal solutsolutions can be used to manipulate blood and manipulate some food products quality or medicine. Hope this helps you