Sound travels in our environment if

 A mechanical wave is a sound wave. Mechanical waves are disturbances that flow across a material medium as a result of collective vibration of the medium's particles.

Sound is a form of energy that needs medium to propagate.

During propagation of sound waves, particles vibrates in their own positions and disturbances created by the vibration of particles moves from one place to another.

Particles vibrates and disturbance moves.

Hence, option (3) is the correct .