6.1: Three alleles control the inheritance of blood groups: $I^A$, $I^B$, and $i$. The alleles are $\boxed{\text{3}}$. 6.2: The type of dominance that occurs in the inheritance of blood group B in a heterozygous woman ($I^B i$) is complete dominance, where the $I^B$ allele is dominant over the $i$ allele. Additionally, the inheritance of ABO blood groups also exhibits codominance between the $I^A$ and $I^B$ alleles. 6.3: Step 1: Determine the genotypes of the parents. Man with blood group AB: $I^A I^B$ Woman heterozygous for blood group B: $I^B i$ Step 2: Determine the gametes produced by each parent. Man: $I^A$, $I^B$ Woman: $I^B$, $i$ Step 3: Construct a Punnett square. $$ \begin{array}{|c|c|c|} \hline \text{Gametes} & I^B & i \\ \hline I^A & I^A I^B & I^A i \\ \hline I^B & I^B I^B & I^B i \\ \hline \end{array} $$ Step 4: List the possible genotypes and phenotypes of the children. Genotypes: $I^A I^B$ $I^A i$ $I^B I^B$ $I^B i$ Phenotypes: $I^A I^B$: Blood group AB $I^A i$: Blood group A $I^B I^B$: Blood group B $I^B i$: Blood group B Genotypic Ratio: $1 I^A I^B : 1 I^A i : 1 I^B I^B : 1 I^B i$ Phenotypic Ratio: $1$ Blood group AB : $1$ Blood group A : $2$ Blood group B The possible genotypes and phenotypes of their children are: $\boxed{\text{Genotypes: } I^A I^B, I^A i, I^B I^B, I^B i}$ $\boxed{\text{Phenotypes: Blood group AB, Blood group A, Blood group B}}$ Send me the next one 📸