Question

what is the necessary condition for the normal hearing to occur?
equal air pressure on both sides of the tympanic membrane
higher pressure on the inner side of the tympanic membrane
higher pressure on the outside of the tympanic membrane

Explanation:

For normal hearing, the tympanic membrane needs equal air - pressure on both sides to vibrate properly. Uneven pressure can distort its vibration and affect hearing.

Answer:

A. Equal air pressure on both sides of the tympanic membrane