What term describes an organism's genetic makeup or allele combinations?

The term that describes an organism's genetic makeup or allele combinations is genotype. Genotype refers specifically to the alleles an individual carries for a particular gene or set of genes, which can include combinations of dominant and recessive alleles. This genetic information is foundational for understanding traits and characteristics that may be expressed in the organism.

Phenotype, on the other hand, refers to the observable traits or characteristics that result from the interaction of the genotype with the environment. Karyotype is a term used to describe the complete set of chromosomes in an organism, which is useful for identifying chromosomal abnormalities but does not directly refer to allele combinations. Allele refers to the different versions of a gene that can exist, rather than the overall genetic makeup of the organism. Thus, genotype is the precise term that encompasses the specific combinations of alleles present in an organism.