An organism's genetic makeup, or the combination of alleles it has, is its ______.

• A. Genotype
• B. Chromosome
• C. Wave
• D. Phenotype

Answer: (A)

Genotype is the organism's genetic makeup, the specific combination of alleles it has. Alleles are the different forms of a gene, and the particular pair an organism carries (such as AA, Aa, or aa) defines its genotype. This is different from the phenotype, which is the trait you can observe or measure—like eye color or flower color—because the phenotype results from how the genotype is expressed, often influenced by the environment. A chromosome is the structure that carries many genes, so it contains the information that contributes to the genotype, but it isn’t the genotype itself. The idea of a wave has no relation to inherited traits. So the genetic makeup being described here is the genotype.