Question

waves have different ways of moving. one type, called longitudinal waves, are a kind of wave that makes particles come closer together in compressions and move farther apart in rarefactions. these waves travel in the same direction that particles are pushed or pulled, creating a pattern of compressions and rarefactions as they move through a medium. sound is an example of this wave and needs a medium to move through.
waves that require a medium to travel through are called mechanical waves. sound is both a longitudinal and mechanical wave. unlike sound, light is a transverse wave, where particles move perpendicular to the waves direction. light doesnt need a medium to travel—it can move through empty space.
what kind of wave requires a medium to travel through?
electromagnetic
light
mechanical

Explanation:

The text clearly states that "Waves that require a medium to travel through are called mechanical waves." This directly answers the question. Electromagnetic waves (like light) do not need a medium as mentioned (e.g., "Light doesn't need a medium to travel - it can move through empty space").

Answer:

C. Mechanical