The blood group which is the universal acceptor is __(i) and the one that is universal donor is __(ii).
(i) AB, (ii) O
AB is the universal acceptor as the blood group contains both A and B antigens; contains no antibodies in its serum. Blood group O on the other hand is the universal donor as it contains neither antigen A nor B, as a result has both anti-A and anti-B antibodies in its serum.