Someone who has the blood type AB had parents with genes.

co dominant

Explanation:

In genetics, “cis” means two things are happening on the same allele. AB blood type is usually a result of getting the A blood type gene from one parent and the B blood type gene from the other parent.

Codominance means that neither allele can mask the expression of the other allele. An example in humans would be the ABO blood group, where alleles A and alleles B are both expressed. So if an individual inherits allele A from their mother and allele B from their father, they have blood type AB.

•there must be variation for the particular trait within a population.

•the variation must be inheritable (that is, it must be capable of being passed on from the parents to their offspring).

•individuals with one version of the trait must produce more offspring than those with a different version of the trait.good

explanation: