There are 2 classifications of waves according to the media of propagation.
Mechanical Waves – needs a medium, an example is sound waves. Sound waves do not travel through a vacuum. Sound waves move by replacing one particle with another. Particles vibrate and that is why we hear the sounds.Electromagnetic Waves and electrostatic waves are one but the same. They do not require a medium. – an example is light waves.
i think it is B) because Sound waves move by replacing one particle with another. Sound waves require a medium to propagate, or move. Light and electromagnetic waves do not require a medium. Electrostatic are not a type of wave.
