Question 18 3 points E' next (Int A sound wave in air is (pick those answers that are appropriate) Amovement of molecules locally to reduce or increase the pressure, but no bulk motions of air. C] A propagating compression of the air followed by a \"rarefacticn\" when the density drops, with the denser regions separated by a wavelength moving through the gas C] A disturbance that locally produces a change in pressure at the frequency of sound, but if you took a snapshot picture would show dense regions separated by a wavelength. C] Bulk motion of the air at the speed of sound from its source to the detector or your ear