Compressed gas has many uses. It can be held in a tank like this with a valve that can be opened to safely release small amounts of gas at a time. The valve usually releases the gas into a tube through which it travels to another container. It is only safe to allow small amounts of compressed gas out at a time.
Answer
A
Any gas would react with whatever air is around it to cause fire and electric bolts when released.
B
A gas would be at such a cold temperature when it is compressed that it would cause everything to freeze around it.
C
A compressed gas would expand very quickly if released uncontrollably and would hit nearby people or objects very hard.
D
Any compressed matter will change the shape of its container, so if the gas were released into a room, it would change the shape of the walls.