Which structures are called bronchioles? A. respiratory passageways that have cartilage in their walls B. the tubes that open from the left and right primary bronchi. C. the tubes that enter a lobule D. the tubes that enter an alveolar sac.
Option C. Terminal bronchioles deliver air to a lobule. Respiratory bronchi- oles deliver air to an alveolar sac. Secondary bronchi diverge from primary bronchi.
