(i) Human beings have three alleles for ABO blood grouping |A||B| and `i`. How many of these alleles can be present in one individual and a gamete ?
(ii) A child has blood group B. If the mother has blood group AB and father blood group A workout the genetypes of the parents and the possible genotypes of the other offsprings.

Explanation

(i) individual (diploid), `:. 2` alleles.
Gamete (haploid), `:. 1` allele.
(ii) A child have blood group B if he or she has genotype `|^(B)|^(B)` or `|^(B)|`.For this the father with blood group must be heterozygous `(l^(A)i)`. Mother has AB blood group, therefore she will have genotype `l^(A)l^(B)`.

i.e., other offspring can have A or AB blood groups.