Gas takes the shape of its container. This is one of the key characteristics of gases, along with being compressible and having particles that move freely.

Here's why:

* No fixed shape: Gas molecules are constantly moving and have very weak attractions to each other. This means they can easily spread out and fill any space they occupy.

* Conforming to the container: If you put gas in a round container, it will take on a round shape. If you put it in a square container, it will become square.

Let me know if you have any other questions about gases!