(a) How the human ear carries out its function of balancing;
- Head movement in any direction affect the fluid/endolymph, In the semi-circular canals, Which are at right angles to each other, The movement forces the sensory/hair cells in the ampulla to set up the impulses, The brain interprets the impulses and relays the impulses to the body muscles for balancing.
(b)(i) Diagram of the Human Ear;

(b)(ii) Description of the structure of the middle ear; The middle ear is an air filled chamber, It connects the ear drum of the oval window fenestra ovalis. It contains three bones/hammer/malleus, anvil/incus and stapes/stirrup/ear ossicles. The malleus is attached to the tympanic membrane/tympanum/eardrum. Each of the bones has direct contact with the one next to it, the eustachian tube is formed at the base of the middle ear . The eustachian tube links the ear to the throat/pharynx.