Final answer:
The characteristic of a mixture is that each substance within it retains its own properties. Mixtures involve combining substances without chemical reactions, allowing them to be separated back into their pure forms.
Step-by-step explanation:
The characteristic of a mixture that you are asking about is that each substance in the mixture retains its own properties. This is because a mixture is formed when two or more substances are combined without a chemical reaction taking place between them. These substances are not in a fixed ratio, they maintain their original properties, and they can be mechanically separated back into their pure forms. For example, if you mix sand and sugar, you can still see the individual grains of each and can separate them by sifting, underscoring that they retain their distinct properties as a mixture.