what colors can blood be
I'm very sure that he is incorrect and that blood is always a red. Could I have some feedback on what color blood really is and why it appears blue. I know that there are two types of blood and that venous blood is a very dark red, but NOT blue. Also that veins appear blue from that outside because of the color of skin. I would like some reputable information on the matter, and would like to show him proof that blood is not blue.