Final answer:
Yes, it is true that a pure substance is made of only one kind of matter and has definite, consistent properties throughout the sample.
Step-by-step explanation:
This statement is indeed true. A pure substance can be identified by its constant composition and set of properties that are the same throughout the sample. This includes elements, which are substances consisting of only one type of atom, like aluminum, and compounds, which are made of two or more types of atoms, like water (H2O).
While mixtures combine substances physically, they do not have uniform properties throughout and can be separated into their individual components, which retain their own properties.