what are the three main parts of the human ear?
['External or outer ear, consisting of: Pinna or auricle. This is the outside part of the ear. ... ', 'Tympanic membrane (eardrum). The tympanic membrane divides the external ear from the middle ear.', 'Middle ear (tympanic cavity), consisting of: Ossicles. ... ', 'Inner ear, consisting of: Cochlea.']