Awoman's first pregnancy is normal but her second pregnancy results in hemolytic disease of the newborn (hdn). the second child needed a transfusion to completely replace the agglutinating blood. the mother is most likely type and both children are most likely _

This is a case of both Rh incompatibility and ABO incompatibility. Since the first pregnancy is normal but the second one resulted in hemolytic disease; it means that in the first pregnancy, the baby was Rh negative which lead the Rh positive mother to produce antibodies against Rh negative blood, which is noted in the second pregnancy leading to hemolytic disease. There may also be a form of ABO incompatibility. The correct answer is that both of her children are type A, Rh negative, and the mother is a type B, Rh positive.