Question

What is a defense against invading organisms in the respiratory tract?

Answer 1

Beating movement in the trachea to make sure any solid particles that pass through the nasal cavity, can be transported via mucus up into the pharynx where it can be swallowed.

Answer 2

Our coughs and sneezes. Also presence of cilia and mucus in the lining of respiratory tract.

Explanation:

Two useful protection reflexes of the respiratory system are the sneezes and coughs .

Those serve the function of foreign irritable or pollutive particles expulsion from the nasal and throat passages.

Hairs, present inside external nares and cilia help in filtering the dust particles, etc. from the air that is breathed in.

Mucus on the other hand can trap many small particulate materials, which could then be pushed towards the outside by ciliary action.