Answer:
Compressions and rarefactions
Explanation:
The wave motion in which the direction of propagation of wave is same the direction of motion of particles of medium is called longitudinal wave motion.
In such type of wave motion, the wave travels in the from of compressions and rarefactions.
The region in which the density of particles is maximum is called compression.
The region in which the density of particles of medium is minimum is called rarefactions.
