Which of the following is genetically dominant in man

The most popularly known blood grouping is the $ABO$ grouping. It is named $ABO$ and not $ABC$, because ' $O$ ' in it refers to having

Parents of blood groups $O$ and $AB$ cannot have a child of group $AB$ because

$A$ woman is married for the second time. Her first husband was $ABO$ blood type $A,$ and her child by that marriage was type $O.$ Her new husband is type $B$ and their child is type $A B$.

What is the women's $ABO$ genotype and blood type?

A person with unknown blood group under $ABO$ system, has suffered much blood loss in an accident and needs immediate blood transfusion. His one friend who has a valid certificate of his own blood type, offers for blood donation without delay. What would have been the type of blood group of the donor friend?

$ABO$ blood groups in humans are controlled by the gene $I$. It has three alleles ­$ I^A, I^B$ and $i$. Since there are three different alleles, six different genotypes are possible. How many phenotypes can occur?