ICSE Class 9 Biology Respiratory System


The common passage for air and food in the human body is the


You experience sudden coughing while swallowing food. Why does this happen?


Why does the trachea not collapse when we exhale air?


Which of the following characteristics enable the smooth exchange of gases at the alveoli?

I Thin membrane

II Network of blood capillaries

III Large surface area 

Human Respiratory System

Learn the mechanism of breathing and various organs of respiratory system. Understand the process of exchange of gases in lungs and tissues.