Something has to do this job, so if it wasn't red blood cells then it'd need to be something else. Unless, of course, mammals had evolved in some other way which did not have a circulatory system.
blood cells do not carry food, blood cells carry oxygen.
White blood cells fight germs and red blood cells carry oxygen.
Red blood cells carry primarily oxygen
Red blood cells carry oxygen around the body and to the cells.
Your red blood cells carry oxygen.
Red blood cells carry oxygen to all the cells of the body.
Red blood cells contain hemoglobin. These cells are also known as erythrocytes.
blood carry oxygen to cells
red blood cells
Oxygen
red blood cells carry oxygen from the lungs through the pulmonary artery to the heart and then to the rest of the body.
red blood cels are the oxygenated cells..[ie carry oxygen]