Answer: The correct answer would be respiratory.
Step-by-step explanation:
The respiratory tracts include: nose, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli.
Structurally, the tract is divided into upper and lower respiratory tract. The upper tract includes nasal cavity, pharynx and a part of larynx. Lower tract includes a part of larynx, trachea, bronchi, bronchioles, and alveoli.
Functionally, the tract is divided into conducting and respiratory divisions. As the name suggests, the conducting zone or division is the part of tract that helps in conducting air at the site of gas exchange. It includes nose, pharynx, larynx, trachea, bronchi, and bronchioles.
In contrast, the respiratory division includes the part of the tract which is involved in actual gas exchange. It includes respiratory brochioles, alveolar duct, and alveoli.