Q. Do all the probable monohybrid crosses for the ABO blood group and give the genotype and phenotype ratios following each cross. Note- there are 3 alleles for each gene so there are more than six possible crosses, and because A and B are co-dominant, there are more than 2 possible phenotypes in some crosses.
Listing all the possible parent crosses for the ABO blood group. There must be 21 possible crosses.