In humans, ABO blood grouping is controlled by multiple alleles: IA (for blood group A), IB (for blood group B), and i (for blood group O). IA and IB are both dominant over i, but codominant with each other. (a) (i) List ALL possible genotypes for each of the four ABO blood groups. (ii) A man of blood group AB marries a woman of blood group O. Using a genetic diagram, determine the blood groups of their possible offspring. (iii) State the probability that a child from this cross will have blood group B. (b) A woman of blood group A (heterozygous) and a man of blood group B (heterozygous) have four children. One child has blood group O. (i) Write the genotypes of both parents. (ii) Using a Punnett square, show all possible genotypes and phenotypes of the offspring from this cross. (iii) What is the probability that their next child will have blood group AB? (c) (i) Explain why blood group is an example of discontinuous variation. (ii) State TWO practical applications of knowledge of blood groups.