Transporting this protein is the main job of your body's erythrocytes
Blood has three important functions: 
Transportation: The blood transports oxygen from the lungs to the cells of the 
body, ... Hemoglobin: A protein inside red blood cells that carries oxygen from the 
lungs... [DOC] [TLE] Haemoglobin [PAR] ... in oxygen, the red blood cells transport it around to every cell in the body  a ... 
oxygen so efficiently because of a special protein inside them: haemoglobin.