$ABO$ blood group is a good example of:

If the mother's blood group is '$A$' and the father's blood group is '$AB$',then the possible blood groups of their children will be:

$A$ man with blood group $A$ marries a woman with blood group $AB$. Which type of offspring would indicate that the man is heterozygous for blood group $A$?

$A$ child has blood group $O$. If the father has blood group $A$ and mother has blood group $B$,work out the genotypes of the parents and the possible genotypes of the other offspring.

If a child has $O$ type of blood group and the father has $B$ type,the genotype of the father will be:

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 $EXCEPT$ . . . . . . .