Asked in Genetics
Substance in red blood cells that carry carbon dioxide away from body cells?
Hemoglobin/haemoglobin (two different spellings of the same thing). It's a protein made up of four separate protein chains, each of which has a heme group, which has as its central feature a porphyrin ring containing an iron atom. This is what gives red blood cells their characteristic color (which is actually more of a dark purple than red when carbon dioxide is bound to the heme groups).