The part of the inner ear that is responsible for hearing is

Explanation

The sacculus is a sensory organ located in the inner ear that primarily functions to detect vertical linear acceleration, meaning it senses movement in the up and down direction, like when you're in an elevator, and helps maintain balance by providing information about your head's position relative to gravity; essentially, it tells your brain if your head is tilting forward or backward. 

The cochlea is the part of the inner ear that is responsible for hearing.

The cochlea is a snail-shaped organ filled with fluid that contains the organ of Corti, which is made up of tiny hair cells that line the cochlea. When sound enters the ear, it causes the fluid in the cochlea to vibrate, which makes the hair cells vibrate and send electrical impulses to the brain. The brain perceives these electrical signals as sound. 

The utriculus, located in the inner ear, functions as a sensory organ that detects linear acceleration and head position in the horizontal plane, essentially sensing side-to-side tilting movements of the head, contributing to our sense of balance by providing information about static equilibrium.The inner ear also contains the semicircular canals, which are responsible for balance. The semicircular canals are filled with fluid and have calcium crystals embedded in their lining.

The function of the ampullae in the ear is to detect head rotation by sensing the movement of fluid within the semicircular canals, sending signals to the brain regarding angular acceleration and deceleration of the head, essentially contributing to balance perception. 

There is an explanation video available .