Question

which statement describes heterogeneous mixtures?
they are made up of two or more pure substances that are not chemically bonded together and appear non - uniform.
the substances they are composed of can only be separated chemically.
the substances they are composed of have fixed ratios between their components.
they are made up of two or more pure substances that are chemically bonded together and appear uniform.

Explanation:

A heterogeneous mixture consists of two or more pure substances that are not chemically bonded. The components are not uniformly distributed, so the mixture appears non - uniform. Also, the substances in a heterogeneous mixture can be separated by physical methods (not just chemical methods as in compounds). In a heterogeneous mixture, there is no fixed ratio of components (unlike in a compound). And if substances are chemically bonded, it is a compound (not a mixture).

Answer:

They are made up of two or more pure substances that are not chemically bonded together and appear non - uniform.