Answer:
There are two main waves; transverse and longitudinal. Transverse waves are like the waves we see in the ocean when we are at the beach. Longitudinal waves consist of sound, but different. Longitudinal waves have more complex properties than sound waves. They follow a consistent pattern of compressions and rarefactions within a(consistent) medium.
In-case you wonder what a medium is, a medium is the substance that carries the wave. Remember that it only transports the wave, and it plays no part in actually making the wave. When waves crash, the particles within the medium are disturbed, so they carry/pass on the disturbance to keep the wave's pattern consistent.
Hope this helps you!