The respiratory system is gas exchange of body systems by the body to get oxygen from outside into the body and drive the gas carbon dioxide out of the body. The gas from the breathing make used of energy. So, the human life needed oxygen, which a people get the oxygen from breathing if your body lacks oxygen to only 2 - 3 minutes it would have been death. However, the work of respiratory system is composed of organs associated with breathing, respiratory system and other elements.