Question

in a transverse wave, how do particles move? *
up and down or side to side (perpendicular with the direction of the wave)
back and forth (parallel to the direction of the wave)
in a circle

Explanation:

In a transverse wave, the motion of particles is perpendicular to the direction of wave - propagation. This means they move up and down or side to side. Particles moving back and forth parallel to the wave direction is characteristic of longitudinal waves, and circular motion is not typical for simple transverse wave particle motion.

Answer:

Up and down or side to side (perpendicular with the direction of the wave)