Answer:
by moistening, heating, and purifying air as it proceeds down the airways
Step-by-step explanation:
The upper respiratory system/tract is made up of the nose, pharynx, paranasal sinuses and larynx.
The upper respiratory tract is responsible for providing a passage for air in the lung, during inhalation and exhalation. It is also responsible for heating and humidifying air as it passes through the respiratory tract. In addition, the upper respiratory tract filters air that flows down the respiratory airways. Therefore the air that reaches the lungs is warmed, humidified and filtered.
Finally, it is is involved in speech, cough and also swallowing.