To solve this problem, we need to identify the characteristics that represent the inheritance of blood groups in humans. Let's analyze each characteristic:$\newline \bullet$a. Dominance:$\newline$ - In the ABO blood group system, the A and B alleles are dominant over the O allele.$\newline$ - This means that if an individual inherits an A or B allele along with an O allele, the phenotype will be A or B, respectively.$\newline \bullet$b. Co-dominance:$\newline$ - The A and B alleles are co-dominant, meaning that if an individual inherits both alleles, the phenotype will be AB, expressing both antigens.$\newline \bullet$