Respiratory system helps us to breathe in and out. The organs involved in our breathing system consist of nose, wind-pipe and lungs.
From the atmosphere, air is taken in by our nose and it goes to lungs through the wind pipe. In the lungs blood absorbs the oxygen from the air.
This oxygen helps in oxidizing the food in the blood to produce carbon-di-oxide and give us energy.
The carbon-di-oxide and water vapors produced in the process are breathed out from the lungs. In the breathing system, lungs play an important role in taking in oxygen and giving out carbon-di-oxide.