What is the elastic medium that sound travels through?

Sound is a mechanical wave that requires a medium to travel through, and the medium must be elastic in nature so that it can support the propagation of sound waves. An elastic medium can be a solid, liquid, or gas.

Air, as the correct answer, is a gaseous medium that is commonly associated with sound transmission. In air, sound waves are created by the vibrations of particles which then propagate through collisions and vibrations of neighboring particles. This allows the sound to travel effectively over distances. While sound can also travel through liquids and solids, air is the medium most commonly encountered in everyday situations.

In contrast, a vacuum is not an elastic medium because it lacks particles to transmit sound. In a vacuum, there are no air molecules or any other particles to conduct sound waves, thus sound cannot travel at all in such an environment. Therefore, while air, liquids, and solids can all serve as elastic media for sound, air is specifically recognized as the medium through which sound is most frequently transmitted in our daily experiences.