Question

how is a pure substance different from a mixture?
pure substances are separated by physical means.
mixtures are made up of more than one component.
mixtures cannot be separated by physical means.
a pure substance is heterogeneous.

Explanation:

A pure substance has a uniform and definite composition. A mixture is a combination of two or more substances. Mixtures are made up of more than one component. Pure substances cannot be separated by physical means (so the first option is wrong). Mixtures can be separated by physical means (so the third option is wrong). A pure substance is homogeneous (so the fourth option is wrong).

Answer:

Mixtures are made up of more than one component.