Which structure is primarily responsible for protecting the airway during swallowing?

The epiglottis plays a crucial role in protecting the airway during swallowing by acting as a flap that closes over the larynx. When a person swallows, the epiglottis moves downward and covers the entrance of the trachea, preventing food and liquids from entering the airway. This mechanism is essential for avoiding choking and ensuring that the respiratory tract remains clear while swallowing occurs.

In terms of the other structures, the trachea and bronchi are primarily involved in the conduction of air to and from the lungs, not in the act of swallowing itself. The pharynx is part of the digestive and respiratory systems and does aid in the process of swallowing, but it does not have the specific role of covering the airway. Thus, the epiglottis is the key structure focused on airway protection during swallowing, making it the correct answer.