Which state of matter adopts the shape and size of the container it is placed in?

• A. Gases
• B. Solids
• C. Liquids
• D. Plasmas

Answer: (A)

Gases are the state of matter that takes both the shape and the volume of their container. Their particles are far apart and move freely, so they spread to fill every part of the available space and expand or compress to match the container’s size. That means a gas has no fixed shape or volume of its own; it simply mirrors the container. Solids keep a definite shape and size regardless of the container, while liquids take the container’s shape but retain their own volume, so they don’t necessarily fill the entire space. Plasmas behave similarly to gases under many conditions, so the description best fits gases.