* Multiple Alleles: This refers to the fact that there are more than two possible alleles for the gene that determines blood type. In this case, there are three alleles: A, B, and O.
* Codominance: This refers to the situation where two different alleles for a gene are both expressed in the phenotype. In the case of blood type, both A and B alleles are dominant to the O allele, and if both A and B alleles are present, they are both expressed, resulting in AB blood type.
