Question

which statement about sound is true because it is a mechanical wave?
it can travel only through air.
it cannot travel through a medium.
it can travel through the vacuum of space.
it must travel through a medium.

Explanation:

A mechanical wave requires a medium to travel. Sound is a mechanical wave. It can travel through solids, liquids, and gases (not just air). It cannot travel through a vacuum.

Answer:

It must travel through a medium.