RESPIRATION:it is defined as oxidation and breaking down of food molecules.
1BREATHING:air movement into &out of lungs
2GASEOUS EXCHANGE AT LUNG LEVEL:EXCHANGE OF
GASES B/T alveoli & blood.
3transport of oxygen from blood capillaries to body cells & return of carbondioxide
4exchanging of oxygen from blood into cells &carbon dioxide from cells to blood
5at last cellular respiration.