What is a combination of two or more substances in which each substance retains its properties?

Mixture

Explanation:

Mixture -

It refers to the composition of various substance in random proportion, where the mixture formed may or may not have uniform composition, and the various components does not lose their identity and there is no chemical change observed, is referred to as mixture.

For example,

The mixture of sand and chalk powder, where both the substances mix together to form a mixture, but still retain their property.

Hence, from the given statement of the question,

The correct term is mixture.