Sound is a wave; regions of compressions and rarefactions are established as the result of the vibrations of the sound source. these compressions and rarefactions result because sound . a) transverse; energy moves perpendicular to particle movement. b) pressure; energy is transmitted longitudinally through the medium. c) longitudinal; particles are trnasmitted longitudinally through a medium. d) transverse; particles move back and forth as energy is transmitted vertically.