Genotype refers to which of the following?

• A. The observable traits of an organism.
• B. The genetic makeup of an organism.
• C. The environmental influences on a trait.
• D. The phenotype expression level.

Answer: (B)

Genotype is the genetic makeup of an organism—the specific set of alleles carried in its DNA. It serves as the hereditary blueprint that influences which traits may be expressed. It differs from phenotype, the observable traits, which result from how the genotype interacts with the environment. The environment can influence whether and how strongly traits are expressed, so the phenotype can vary even with the same genotype. The other options describe the outward traits or environmental effects, not the genetic content itself.