6. As we breathe, dirt, pollen, and microorganisms may enter the lungs and irritate these. what prevent(s) this is happening?
A. Gas exchange.
B. Humidification of air in the nasal cavity.
C. Production of mucus and beating of cilia.
D. Movement of blood into the alveoli for removal of wastes.

7. Some structures in the lungs can be compared to a bunch is attached to?
A. Alveolus
B. Bronchi
C. Tranchea
D. Bronchiole

8. If the flow of air INTO the respiratory system is traced, which of the following flow charts would show the correct sequence?
A. Nostrils➡️pharynx➡️nasal cavity➡️larynx➡️trachea➡️Bronchiole➡️​bronchi➡️alveoli
B. Nostrils➡️nasal cavity➡️bronchi➡️bronchiole➡️larynx➡️pharynx➡️alveoli
C. Nostrils➡️nasal cavity➡️pharynx➡️larynx➡️trachea➡️bronchi➡️bronchiole➡️alveoli
D. Nasal cavity➡️nostrils➡️pharynx➡️trachea➡️lungs➡️bronchiole➡️alveoli➡️bronchi

-Hope you can help me of this, thanks in advance!​