The function of hair follicles inside the nose is:

The correct option is D To trap germs and dust particles in the air.
The skin of the nasal chamber contains a fine amount of tiny hairs. These are responsible for trapping the dust particles and germs that are inhaled with the air. The mucus also performs the trapping of dust and germs because of its richness in mucins and due water absorbing capacity, it also moistens the air. Therefore, it is advised to breathe in via nose and not through the mouth as the buccal cavity cannot perform the trapping of germs and dust.

Hence, the correct answer is 'To trap germs and dust particles in the air'