Answer:
Sound waves travel through the air.
Explanation:
As a sound wave travels through a medium, it will often reach the end of the medium to encounter an obstacle or perhaps another medium through which it could travel. In a sound wave, a portion of the energy carried by the sound wave will pass across the boundary and out of the transmission, and a portion of the energy carried by the sound wave will reflect off the boundary, remain in the transmission, and travel in the opposite direction.