Biology

The nasal cavity plays a key role in the first stage of air filtration.

It is lined with mucus and tiny hair-like structures called cilia.

These structures trap dust, dirt, and pathogens, preventing them from entering the lungs.

Additionally, the nasal cavity warms and moistens the air, making it suitable for exchange in the delicate alveoli of the lungs.

Option A (Alveoli) is incorrect because alveoli ar...