Answer:
Epithelial cells
Explanation:
It is epithelial cells because epithelial cells are cells that are found in the body surfaces. The conducting passage ways of trachea, nasal cavity, bronchi, bronchioles are lined with a special type of epithelial cells called pseudo stratified columinar epithelial cells which is ciliated and have mucus secreting globlets. These cells are found in the trachea because they have thin surface that facilitate diffusion, moisten the passage ways and protect the trachea from pathogens.
