Question

1. particles move parallel to the direction the wave travel in a ______ wave.

a medium
b longitudinal
c transverse
d frequency

Explanation:

In a longitudinal wave, particles of the medium move parallel to the direction of wave - propagation. In a transverse wave, particles move perpendicular to the wave - propagation direction. Medium is the substance through which a wave travels and frequency is the number of wave cycles per unit time.

Answer:

B. Longitudinal