Mass is the (2. amount of matter) in an object.
An object’s mass (2. does not change).
The amount of space that matter occupies is (3. volume).
All states of matter—solids, liquids, and gases—have volume. While solids have a definite shape and volume, liquids have a definite volume but take the shape of their container, and gases fill the entire volume of their container, adapting to its shape.