Which type of substance retains its chemical and physical properties when formed?

The correct choice is pure substances. A pure substance is defined as having a uniform and consistent composition throughout, meaning that it retains its distinct chemical and physical properties when formed. This includes elements like gold or oxygen, as well as compounds like water or sodium chloride, which maintain their unique properties regardless of their state or the environment around them.

In contrast, solutions consist of a solute dissolved in a solvent, which can change the physical properties of the solute, while compounds are formed when two or more elements chemically combine, resulting in new properties that differ from the individual elements. Suspensions, on the other hand, consist of particles that are distributed throughout a fluid but remain separate rather than creating a uniform substance.

Understanding the distinction between pure substances and mixtures, like solutions and suspensions, is crucial in the context of hair coloring, as it relates to how different color formulas interact and perform on the hair.