Answer
a. homogeneous mixture;
b. heterogeneous mixture;
c. pure substance, element;
d. pure substance, compound
Work Step by Step
A pure substance is made up of one single type of atom or molecule. An element can't be broken down into smaller, simpler units. A compound is made up of two or more elements.
A mixture is made up of two or more different types of atoms or molecules. A homogeneous mixture is made up of atoms and molecules that are mixed uniformly. A heterogeneous mixture is made is made up of atoms and molecules that are mixed randomly.