Which of the following describes a combination of substances that are not chemically combined?

A mixture refers to a combination of substances in which the individual components retain their own properties and can be separated by physical means. In a mixture, the substances can include solids, liquids, or gases, and they simply coexist without undergoing any chemical changes. This means that the components can be present in varying amounts and can be easily removed or isolated from one another.

In contrast, a compound is a substance formed when two or more elements chemically bond together, resulting in a new substance with distinct properties. Solutions are a type of mixture where one substance is dissolved in another, creating a homogeneous mixture, while elements are pure substances consisting of a single type of atom. Thus, a mixture is accurately described as a combination of substances that are not chemically combined.