Muddy water can be mixed up and look the same throughout. However, over time the mud will settle to the bottom and the brown water will rise to the top. Muddy water is an example of
a homogeneous mixture or "solution"
a pure substance.
a compound
a special kind of heterogeneous mixture called a suspension

Suspension (a special type of heterogeneous mixture)

the molecules move in straight line until they collide with each other or with the walls of the container. collisions are perfectly elastic; when two molecules collide, they change their directions and kinetic energies, but the total kinetic energy is conserved.

explanation: