What would likely happen if the Eustachian tube is blocked?

When the Eustachian tube is blocked, one of the primary consequences is a lack of ventilation in the middle ear. The Eustachian tube serves a critical function in equalizing air pressure in the middle ear with that of the external environment. If the tube is obstructed, pressure cannot be equalized, leading to potential discomfort and various auditory problems. Moreover, the inability of the middle ear to ventilate can result in a negative pressure environment, which may contribute to fluid retention and the development of infections, such as otitis media.

Ventilation is essential for maintaining a healthy middle ear environment, as it helps to keep the space clear of fluid and supports proper drainage. Thus, the blockage can lead to various complications, including impaired hearing, as sound transmission is affected. Without adequate ventilation, the normal functioning of the middle ear is compromised, illustrating why the option indicating lack of ventilation is indeed the correct answer.