Final answer:
Normally only air passes through the nasopharynx, which functions primarily in respiration and speech. The soft palate prevents food from entering the nasopharynx during swallowing. The correct option is 2) air.
Step-by-step explanation:
Normally, only air passes through the nasopharynx. The nasopharynx is the upper part of the pharynx that is connected to the nasal cavities. Its primary function is related to respiration and speech, and it is not a passageway for food. During the process of swallowing, the soft palate and uvula close off the nasopharynx to prevent food and other swallowed substances from entering the nasal cavity.
In contrast, the oropharynx and the laryngopharynx, which are parts of the pharynx situated below the nasopharynx, are involved in both respiratory and digestive processes, thus allowing the passage of both air and food. The epiglottis, a flap of connective tissue, closes over the opening to the larynx when we swallow food to prevent choking, directing food toward the esophagus and away from the airway.