7. which of the following has to happen before the eardrum begins to vibrate with the same frequency as the source of the sound waves?
a. vibrations have to be transmitted to the fibers of the auditory nerve.
b. impulses have to be sent to the brain through the auditory nerve.
c. the brain has to interpret the direction from which the sounds are being delivered.
d. the outer ear has to collect the sound waves and lead them to the middle ear.

Answer : Option D) The outer ear has to collect the sound waves and lead them to the middle ear.

Explanation : Hearing is dependent on a series of complex steps that change vibrations of sound waves in the air into electrical signals. At first the vibrations of sound waves gets collected by the outer ear and from there sound waves travel through a narrow passageway called the ear canal, which leads to the eardrum. The eardrum vibrates from the incoming sound waves and sends these vibrations to three tiny bones in the middle ear. The auditory nerve then carries these signals to the brain.