The cilia of the trachea transfer:

The nasal cavity is divided by a central septum and contains several bony projections called:

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

Definition / Explanation: $(1)$ Alveoli

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

Which of the following structures increases the respiratory surface of the lung in a rabbit?