Genes located on homologous chromosomes for the same trait are called.....

The number of phenotypes in $ABO$ blood group is

$ABO$ blood grouping in humans is controlled by the gene $I$. It has three alleles: $I^A, I^B,$ and $i$. Due to these three different alleles,six different genotypes are possible. How many phenotypes can be formed from these?

$A$ man with blood group $B$ marries a woman with blood group $A$ and their first child has blood group $B$. What is the genotype of the child?

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

What is the possible blood group of children whose parents are heterozygous for $A$ and $B$ blood groups?