Q1. The red blood cells of which of the following blood groups contain both A and B antigens?
A A
B B
C AB Correct
D O
Explanation
In the ABO blood-group system, antigens are present on the surface of red blood cells. Blood group AB has both A and B antigens on its red blood cells, so it matches the condition in the question. Blood group A has only A antigen, while blood group B has only B antigen. Blood group O has neither A nor B antigen on the red blood cells. This antigen pattern is the basis for ABO compatibility in blood transfusion.