Answer: Option A
Explanation:
The main purpose of the breathing by nose is to provide the optimum air quality which is required by the body.
The air that enters the nasal passage is moisten and heated when it passes through the nasal cavity.
When it travels through the passage the pathogens are killed by the mucous that lies in these area.
In this way, the air is filtered by the nasal passage. Hence, the correct answer is option A.