Final answer:
The Eustachian tube is the structure that connects the throat with the middle ear, allowing for the equalization of air pressure on the eardrum to prevent discomfort and protect the inner ear.
Step-by-step explanation:
The structure that connects the throat with the middle ear to equalize air pressure on the eardrum is known as the Eustachian tube. This small passage allows for the equalization of pressure across the tympanic membrane, which is critical especially during situations where air pressure changes drastically, such as during a flight or while scuba diving. When the air pressure is not equalized, it can result in a significant force on the eardrum and lead to discomfort or even pain, sometimes exacerbated by infections causing fluid buildup. The Eustachian tubes help to balance this pressure and protect the inner ear.