Final answer:
The A. nasopharynx is the region of the pharynx not considered part of the digestive system, as it is involved only in breathing and speech.
Step-by-step explanation:
The region of the pharynx not considered part of the digestive system is the nasopharynx. The pharynx is divided into three main regions: the nasopharynx, the oropharynx, and the laryngopharynx. The nasopharynx is involved only in the breathing and speech, meaning it is not part of the digestive system, whereas both the oropharynx and the laryngopharynx are involved in the passage of both air and food, and therefore are parts of the digestive system.
The oropharynx is a passageway for both air and food, connecting to the laryngopharynx, which also serves a dual role. The laryngopharynx is the area that leads to the divergence of the respiratory and digestive tracts and is involved in digestion.
The region of the pharynx not considered part of the digestive system is the nasopharynx. The nasopharynx is involved in breathing and speech, but not in digestion. On the other hand, the oropharynx and laryngopharynx are subdivisions of the pharynx that are used for both breathing and digestion.