Final answer:
Gas conditioning occurs as air travels through the twisted pathways of the respiratory tract, allowing more time for temperature and humidity adjustments before reaching the lungs where gas exchange takes place.
Step-by-step explanation:
Gas "conditioning" is facilitated by the twisted pathways through the respiratory tract as this means the air gets to stay longer. This process allows for more efficient gas exchange, as the pathway of air through the system is lengthened, providing air more time to condition, or adjust temperature and humidity, to optimal levels before reaching the gas exchange sites. As air travels through the trachea and the branching passages of the lower respiratory tract, it reaches the lungs where the actual gas exchange with the bloodstream occurs.