It prevents the entry of food into the larynx.

The phagocytic cells of the pulmonary alveoli are called ...... .

Which of the following organs is not a part of the abdominal cavity?

Select the correct statements about alveoli from the following.
$i$. Air sac of each terminal bronchiole shows $10$ to $12$ alveoli.
$ii$. Each alveolus is surrounded by a network of capillaries.
$iii$. They are lined by ciliated pseudostratified epithelium.
$iv$. They provide surface area for exchange of gases.
$v$. There are about $700$ million alveoli in the lungs.

The alveoli contain ..........

The lungs contain a large number of narrow tubes known as: