Matching blood group before marriage is important. This is to prevent Rh incompatibility. Rh incompatibility can lead to erythroblastosis fetalis (Hemolytic disease of the newborn-HDN). Fetal RBC gets destroyed & newborn may get severe anaemia, jaundice. This jaundice is more severe than Physiological jaundice ( which is the most common and will usually resolve on its own).   In very severe form, a fetus may die due to heart failure. This is mediated by the antigen-antibodies reaction. Transfer of maternal antibodies across the placenta occurs. This happens when Rh +ve man marries Rh-ve lady.    So Rh +ve man should try to avoid marrying Rh-ve lady.   Matching blood groups for marriage :: Boy : A = Girl : A & AB  Boy : B = Girl : B & AB  Boy : O = Girl : O, A, B & AB  Boy : AB = Girl : AB  Boy : Rh+ve = Girl : Rh+ve  Boy : Rh-ve = Girl : Rh+ve & Rh-ve.    Blood groups that do not match for marriage :: Boy : A = Girl : O & B  Boy : B = Girl : O & A  Boy : AB = Girl : O, A & B  Boy : Rh+ve = Girl : Rh-ve.

Answer: C) Russia Explanation: Here the relation between the given words is that the first word is the National animal of the second word. As Peacock is the national bird of India, similarly Bear is the national animal of Russia.   Hence, Peacock : India :: Bear : Russia.