The organism's genetic constitution, including alleles present, is called the

• A. Genotype
• B. Karyotype
• C. Genome
• D. Phenotype

Answer: (B)

The term that matches “the organism's genetic constitution, including alleles present” is genotype. This describes the specific alleles an organism carries at each gene locus, reflecting its genetic makeup. In a diploid organism, you carry two alleles for each gene, and the combination (like A with a, or two copies of A) constitutes the genotype.

A karyotype, by contrast, is the number and structure of chromosomes in a cell—useful for spotting chromosomal abnormalities, but it doesn’t specify the particular gene variants you have. A genome is the entire set of genetic material, the full sequence of DNA, not just which alleles are present. Phenotype refers to observable traits and characteristics that result from the genotype interacting with the environment.