Which term describes the genetic makeup of an organism, such as AA or Bb?

The term that describes the genetic makeup of an organism, such as AA or Bb, is genotype. Genotype refers specifically to the set of alleles an individual possesses for a particular trait, which can include both dominant and recessive alleles. For example, in the case of AA, both alleles are identical and represent a homozygous condition, while Bb represents a heterozygous condition, where the alleles are different.

In contrast, phenotype refers to the observable traits or characteristics of an organism, which are influenced by the genotype along with environmental factors. Heterozygous and homozygous describe specific types of genotypes: heterozygous indicates two different alleles for a trait, while homozygous indicates the presence of two identical alleles. Thus, the proper term for the genetic makeup itself is indeed genotype.