(N/A) The outer ear $(pinna)$ collects sound waves from the surroundings.
These sound waves pass through the auditory canal to the eardrum,a thin membrane.
When a compression of the medium reaches the eardrum,the pressure increases,forcing it inward.
Conversely,when a rarefaction reaches the eardrum,it moves outward,causing the eardrum to vibrate.
These vibrations are amplified several times by the three bones in the middle ear ($malleus$,$incus$,and $stapes$).
The middle ear transmits these amplified pressure variations to the inner ear.
In the inner ear,the $cochlea$ converts these pressure variations into electrical signals.
These electrical signals are sent to the brain via the auditory nerve,where the brain interprets them as sound.