How is a phenotype defined in the context of genetics?

In genetics, a phenotype refers to the physical expression or observable characteristics of a trait in an organism. This includes characteristics such as height, color, shape, and behavior, which can result from the interaction between the organism's genetic makeup (genotype) and environmental factors.

The phenotype is essentially how the genetic information is manifested in the organism's appearance and traits. For example, in plants, the phenotype may include flower color, leaf shape, and growth habit, all influenced by specific genes as well as environmental conditions. This definition highlights the importance of both genetics and environment in shaping the observable traits of an organism.

The other options describe other concepts in genetics that are distinct from the definition of phenotype. Genetic makeup is more accurately referred to as the genotype, while a dominant gene refers to specific alleles that can influence the phenotype, rather than describing the phenotype itself. Similarly, an allele is a variant form of a gene, which contributes to the genotype but doesn’t directly define what the observable traits are in terms of phenotypic characteristics.