This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
During inspiration, the main current of airflow in a normal nasal cavity is through: 
Select and explain. 
A. Middle pa of the cavity in middle meatus in a parabolic curve, B. Lower pa of the cavity in the inferior meatus in a parabolic curve, C. Superior pa of the cavity in the superior meatus, D. Through olfactory area
A: Middle pa of the cavity in middle meatus in a parabolic curve
Answer: A: Middle pa of the cavity in middle meatus in a parabolic curve 
Explanation: Nose is the natural pathway for breathing. During quiet respiration: Inspiratory air current passes through middle pa of nose between the turbinates and nasal septum. Very little air passes through inferior meatus or olfactory region of nose. Therefore, weak odorous substances have to be sniffed before they can reach olfactory, area. During expiratorn, air current follows the same course as during inspiration, but the entire air current is not expelled directly through the nares. Friction offered at limen nasi conves it into eddies under cover of inferior and middle turbinates and thus sinuses are ventilated during expiration.