What is the role of the cilia that line the respiratory tract?

Hi there!! Cilia are very small fine hairlike projection's/tissues, who's primary responsibilities in the airway is to make sure that it is clear. To be more specific... Cilia line the airways' trachea down. These cilia will do two things; They will trap germs and particulate matter (dust, dander, etc..), before then moving the trapped objects upward to the area where the airway meets the larynx, where you then swallow it... Additionally you can expel it eventually with a cough.

Because you get to live without any hoses bothering u

The answer is b. increased blood flow reduces nerve sensitivity