multiple alleles incomplete dominance homozygous recessive heterozygous dominant
I gave my students this multiple choice question: Sickle cell anemia is a condition that affects the shape of a red blood cell. An unaffected individual can be represented with the genotype AA. An affected individual can be represented with the genotype SS. Individuals that are carriers have the genotype AS. Which is the best description of sickle cell anemia?

Only one answer is correct among these 4 choices:
- multiple alleles
- incomplete dominance
- homozygous recessive
- heterozygous dominant

Could you tell me which one is correct?

incomplete dominance