Answer:
Force
Explanation:
Crests are the high points of a transverse wave. The amplitude is the measure of the size of the disturbance from a wave (half the distance from the trough and crest) or (depending on the compression coils). The wavelength is the the distance between one point on a wave and the nearest point just like it.
Here they don't talk about mass, notice they are mostly talking about force and pressure.