Which describes the observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences?

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

Answer: (B)

The observable traits of an organism—the way it looks, behaves, or functions—are its phenotype. This reflects how the genetic instructions (genotype) are expressed in the real world, influenced by environmental conditions. For example, genes may give the potential for tall height, but factors like nutrition and health during development can affect the actual height achieved. Similarly, a plant might have genes for large leaves, yet insufficient water or light can limit their size. The genotype is the genetic makeup that carries alleles, the specific gene variants, while the genome refers to the organism’s entire set of genetic material. Phenotype is the best description of the observable physical or biochemical characteristics determined by both genetic makeup and environment.