Final answer:
The statement about the low radii of individual bronchioles and their high total cross-sectional area resulting in low resistance in the conducting zone is true. The extensive branching of the bronchioles allows for efficient airflow with minimal resistance to the respiratory zone.
Step-by-step explanation:
The statement 'The radii of individual bronchioles is low, but their total cross-sectional area is high, resulting in an overall low resistance in the conducting zone' is true. Each bronchiole is indeed quite small in diameter, about 1 mm, but they multiply and branch out extensively in the lungs, leading to a large total cross-sectional area. This extensive branching results in a distributed airflow, which decreases the resistance experienced by air moving through the conducting zone. The respiratory zone starts from where the terminal bronchioles connect to the respiratory bronchioles, leading to alveolar ducts and then to the alveolar sacs, where gas exchange occurs.