Taeniae are found in:

Which of the following prevent the collapsing of the trachea?

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 structure which prevents the entry of food into the respiratory tract is

Select the $INCORRECT$ statement.

The gaseous exchange between blood and air does not occur in