Acolloid is a. solid particles dispersed in water. c. a gas. b. a suspension where the particles settle out. d. amalgam.

The correct answer is a: solid particles dispersed in water if the particles have a diameter between approximately 1 and 1000 nm
A colloid is a mixture in which one substance is evenly dispersed in another of substance. The dispersed substance is called dispersed phase (the suspended particles) and the medium of suspension is a continuous phase. The types of colloids include sol (solid particles in a liquid like blood), emulsion (two liquids like milk), foam (gas in a liquid or solid like whipped cream), and aerosol (solid or liquid in a gas like fog).