Final answer:
Warming and humidifying air in the nasal passages helps protect the lungs from dehydration and infection, and it prevents damage to the lungs by removing particles and conditioning the inhaled air.
Step-by-step explanation:
Air is warmed and humidified in the nasal passages. This helps to prevent damage to the lungs from dehydration and ward off infection by trapping particulate matter and equilibrating the air to the body conditions. The processes of warming, humidifying, and removing particles are important protective mechanisms that prevent damage to the trachea and lungs, help in reducing rates of lung infection, and prevent cell damage caused by cold air.