In which of the following phenomena can both dominance and codominance be observed?

$A$ child with a mother of $O$ blood group and a father of $A$ blood group will have which of the following blood groups?

If the father has $AB$ blood group and mother has $A$ blood group,then the children born to them will have the following blood groups $EXCEPT$ . . . . . . .

What are the products of the $I^A$ and $I^B$ alleles?

The genotypes of a husband and wife are $I^A I^B$ and $I^A I^O$. Among the blood groups of their children, how many different genotypes and phenotypes are possible?

Explain the concept of multiple alleles.