In which of the following parts of organisms, the process of gaseous exchange during respiration does not take place?

Gaseous exchange occurs only where the respiratory surface is thin, moist and well-vascularised. The moist skin of earthworms (cutaneous respiration), the gills of aquatic animals like Pila (branchial respiration), and the alveoli of human lungs are all sites of actual gas exchange. The bronchi of humans, however, are merely conducting airways lined with cartilage and pseudostratified ciliated epithelium; their walls are too thick and they are not surrounded by gas-exchange capillaries. Hence no gaseous exchange occurs in the bronchi.