What term refers to the genetic makeup of an organism?

The term that refers to the genetic makeup of an organism is "genotype." The genotype encompasses the specific set of genes inherited from an organism’s parents, representing the genetic blueprint that influences physical traits, behaviors, and susceptibilities to certain health conditions.

While phenotype refers to the observable characteristics or traits of an organism, such as color, size, and shape, it is influenced by the genotype and environmental factors. Polymer is a broad term that applies to large molecules composed of repeating subunits, often not directly related to genetics. Heterozygous describes a specific genetic condition where an individual has two different alleles for a particular gene, which pertains to the genotype but does not define the term itself. Hence, the correct answer, genotype, accurately describes the overall genetic composition.