Question

a___ has the same volume in any container, but takes the shape of the container.

Explanation:

Liquids have a definite volume but take the shape of their container. This is a fundamental property of the liquid state of matter. Solids have a definite shape and volume. Gases have no definite shape or volume (they expand to fill the container). Plasma also has no definite shape or volume in the same sense as gases (it's an ionized gas - a high - energy state).

Answer:

Liquid