Apart from breathing, what is the other primary function performed by the nasal cavity in our respiratory system?

What is the essential feature of respiratory organs in different terrestrial animals?

Explain the mechanism of gaseous exchange between tissues and blood.

How does the air necessary for breathing enter the human body?

How are the lungs designed in human beings to maximize the area for exchange of gases?

In the experimental setup to demonstrate that $CO_2$ is released during respiration, name the substance taken in the small test tube kept inside the conical flask. State its function and the consequence of its use.