Final answer:
The respiratory bronchioles are not part of the conducting zone but are a part of the respiratory zone, which is involved in gas exchange. The correct answer to the question is D.
Step-by-step explanation:
the respiratory bronchioles. The conducting zone of the respiratory system includes all the structures that lead air in and out of the lungs without being directly involved in gas exchange. These include the nasal cavity, pharynx, trachea, primary bronchi, and the bronchioles, specifically up to the terminal bronchioles. The respiratory bronchioles, however, are part of the respiratory zone, which starts where the terminal bronchioles join the respiratory bronchioles. The respiratory zone includes structures that are directly involved in gas exchange such as respiratory bronchioles, alveolar ducts, and alveoli.
The conducting zone of the respiratory system includes the organs and structures not directly involved in gas exchange. It consists of the nasal cavity, pharynx, trachea, bronchi, and most bronchioles. The primary function of the conducting zone is to provide a route for incoming and outgoing air, remove debris and pathogens from the incoming air, and warm and humidify the incoming air.