Which of the following does not occur when we hear a sound? the eustachian tubes constrict the fluid in the cochlea moves sound waves enter the ear canal and strike the eardrum the auditory nerve carries nerve impulses to the brain

Option A, The Eustachian tubes constrict

Explanation:

The Eustachian tubes basically equalizes the pressure in the middle ear whenever our ears are exposed to a varying outside pressure as compared to the pressure inside the ear. This happens very often with people who travel through flight or aqua divers, mountaineers etc. Thus, the role of Eustachian tubes is not very relevant when we are hearing something. It works even when we are not hearing anything.

Hence option A is correct.

primary succession occurs in essentially lifeless areas regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier. secondary succession occurs