In humans, respiration occurs in the following steps. Arrange these steps in the correct order.
A. Diffusion of $\text{O}_2$ and $\text{CO}_2$ between blood and tissues.
B. Diffusion of $\text{O}_2$ and $\text{CO}_2$ across alveolar membrane.
C. Pulmonary ventilation by which atmospheric air is drawn in and $\text{CO}_2$ rich alveolar air is released out.
D. Cellular respiration.
E. Transport of gases by the blood.
Choose the correct answer from the options given below :

The steps of respiration in humans occur in the following sequence:

First, pulmonary ventilation (breathing) takes place, by which atmospheric air is drawn in and $\text{CO}_2$ rich alveolar air is released out (C).

Second, diffusion of gases ($\text{O}_2$ and $\text{CO}_2$) occurs across the alveolar membrane (B).

Third, transport of gases is carried out by the blood (E).

Fourth, diffusion of $\text{O}_2$ and $\text{CO}_2$ takes place between the blood and tissues (A).

Finally, cellular respiration occurs, where $\text{O}_2$ is utilised by the cells for catabolic reactions and $\text{CO}_2$ is released (D).

The correct sequence is C, B, E, A, D.

Answer: C, B, E, A, D