We respire by breathing in the air,where oxygen is.and breathing it out with the waste product or the carbon dioxide.there are 4 phase of respiration.
1.BREATHING-it is the act of inhaling and exhaling air.
2.EXTERNAL RESPIRATION-Exchange of oxygen and carbon dioxide between the air and blood in our lungs.
3.INTERNAL RESPIRATION-the exchange of oxygen and carbon dioxide between the blood and the body cells.
4.CELLULAR RESPIRATION-The process of using oxygen to break down sugar in food,producing ATP in cells and releasing carbon dioxide as a waste product.