Answer:
compression and rarefaction
Explanation:
This kind of wave is called a longitudinal wave and an example of such a wave is a sound wave. The center of compression can be analogous to the top of a crest of a transverse wave while the center of the rarefaction would be analogous to the bottom of the trough of a transverse wave.
The definition is the study of life
The answer to this question is b syphillis because of cervical discharge