Which of the following terms refers to an organism's genetic makeup or allele combinations?

The term that refers to an organism's genetic makeup or allele combinations is genotype. Genotype encompasses the specific set of genes inherited from an organism's parents, including various combinations of alleles, which can be dominant or recessive. Understanding genotype is crucial for predicting inheritance patterns and explaining the potential traits that may be expressed in the phenotype, or the observable characteristics of the organism.

In contrast, phenotype describes these observable traits and is influenced not only by the genotype but also by environmental factors. The term dominant refers to a specific type of allele that can mask the expression of another allele. Heterozygous describes a genotype consisting of two different alleles for a particular gene, but it does not encompass the broader definition of all genetic makeup. Therefore, the correct answer emphasizes the full picture of genetic information.