Final answer:
A salad dressing that must be shaken to mix the particles is a suspension, a heterogeneous mixture where particles are large enough to settle.
Step-by-step explanation:
A bottle of salad dressing that must be shaken before use to evenly mix the particles is classified as a suspension. Suspensions are heterogeneous mixtures in which the particles are large enough to eventually settle out. In contrast, a colloid has particles that are larger than those in a solution but still too small to settle out, and a solution is a homogeneous mixture with particles the size of ions or small molecules that do not settle out.
Given examples from the provided information show that ranch-style salad dressing is a heterogeneous mixture falling into the category of a suspension, similar to mud, which is cloudy and where particles can settle upon standing.