Which of the formed elements of the blood determines ABO blood types?
A. White blood cells
B. Red blood cells
C. Antibodies
D. Plasma
I know that the answer is either red blood cells or antibodies and I know this: Red blood cells have special molecules called antigens on their surfaces. Each person has either the A antigen, the B antigen, both the A and B antigens, or none of the antigens on their red blood cells. A person’s immune system will respond to these antigens by reacting with protein antibodies, which circulate in their blood plasma. But, I'm still not sure which is the correct answer.