The mechanism of the human body which facilitates the exchange of respiratory gases is called:

In the following questions, a statement of Assertion $(A)$ is followed by a corresponding statement of Reason $(R)$. Mark the correct answer as:
Assertion $(A)$: Exchange of oxygen and carbon dioxide occurs between blood vessels and alveoli.
Reason $(R)$: Oxygen diffuses from alveoli to blood vessels and carbon dioxide diffuses from blood vessels to alveoli.

Which contains more carbon dioxide: exhaled air or inhaled air? Why?

Why do we need a respiratory pigment to perform respiration?

The blood leaving the tissues becomes richer in

Name the pores in a leaf through which respiratory exchange of gases takes place.