What type of waves can only travel through a medium?

Mechanical waves

Explanation:

Mechanical waves  are the waves that can travel only through a medium. Mechanical waves are disturbance of matter and require medium to transfer the energy. There are three types of mechanical waves that include  transverse wave, longitudinal wave and surface wave.

Some of the examples of mechanical waves are sound waves and seismic waves etcetera.

Hence, the correct answer is "Mechanical waves".

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