Study the diagram above and answer the following questions: (a) How many alleles are involved in blood grouping? (b) A person having 'AB' blood group…

Three alleles

Co-dominance.

Yes, they can have a child with ‘O’ blood group

Cross: Father (A, $\displaystyle \mathrm{I}^{\mathrm{A}} \mathrm{i}$) x Mother (B, $\displaystyle \mathrm{I}^{\mathrm{B}} \mathrm{i}$) -> gametes $\displaystyle \mathrm{I}^{\mathrm{A}}$, $\displaystyle \mathrm{i}$, $\displaystyle \mathrm{I}^{\mathrm{B}}$, $\displaystyle \mathrm{i}$ -> children $\displaystyle \mathrm{I}^{\mathrm{A}} \mathrm{I}^{\mathrm{B}}$ (AB), $\displaystyle \mathrm{I}^{\mathrm{A}} \mathrm{i}$ (A), $\displaystyle \mathrm{I}^{\mathrm{B}} \mathrm{i}$ (B), $\displaystyle \mathrm{i} \mathrm{i}$ (O).