This is because the direction of wave propagation is parallel to the direction of the oscillation of the particles causing the wave to propagate.
Yes. Sound waves are longitudinal waves.
a sound wave is longitudinal. this is because the wave compress and expand the air particles around them. ( that is what a longitudinal wave does).
a longitudinal wave is a vibration like sound therfore a longditudinal wave is a sound.
I could say longitudinal