It prevents the entry of food into the larynx.

Trapped dust particles are pushed out of the respiratory tract by:

Identify the component of the respiratory system which displays the features given below and choose the correct option:
$I.$ Double layered
$II.$ Fluid contained in it reduces the friction on the lung surface
$III.$ Its outer layer is in contact with the thoracic wall
$IV.$ Its inner layer is in contact with the lungs

Identify $X$ from the figure.

The wall of the alveoli is composed of which type of tissue?

Choose the incorrect statement.