Answer:
Compression and rarefaction
Step-by-step explanation:
A longitudinal wave have the particles of the medium vibrate in the same direction as the wave itself. longitudinal wave travels through a series of compression and rarefaction. compression is the region in the longitudinal wave where the vibrating particles are closest together. On the other hand, rarefaction is the region in the longitudinal wave where the vibrating particles are far apart. The regions of rarefaction and compression comes one after another in the wave.