Answer:
cochlea.
Step-by-step explanation:
When a sound wave hits the eardrum, the eardrum moves tiny bones — the malleus, incus, and stapes — which subsequently move.
This movement is picked up by the mechanoreceptors in the inner ear, which exist on hair cells containing cilia between the end of the semicircular canals and the vestibule.
When the cilia move, the cells create an impulse that is sent through the cochlea to the eighth cranial nerve, which carries the impulse to the brain.
The brain then interprets the information as a specific sound.