What does the respiratory system do

I jest need to know what the respiratory system does for homework. Just a brief explanation!!!

The respiratory system is the process of breathing its when you breathe in Oxygen which goes into your mouth down your windpipe and into your lungs by the red bloods cells and in the lungs it gets converted into Carbon Dioxide and taken back out the lungs and up the wind pipe and back out when you breath out

The function of the human respiratory system is to transport air into the lungs and to facilitate the diffusion of Oxygen into the blood stream. Its also receives waste Carbon Dioxide from the blood and exhales it.

~Tweek

The respiratory system shows how to breath and the way you breath