There is no atmosphere on moon. Can you hear each other people on the moon’s surface?

Choose the correct word/words to complete the following sentence —

When sound travels in a medium ………. (the particles of the medium, the source, the disturbance, the medium) travels in form of a wave.

What is a longitudinal wave? In which medium: solid, liquid or gas, can it be produced?

What is a transverse wave? In which medium: solid, liquid or gas, can it be produced?