What does phenotype refer to in genetics?

Phenotype refers to the observable physical characteristics or traits of an organism that result from the interaction of its genotype (the genetic makeup) with the environment. This includes features such as height, eye color, and other visible traits. The answer is correct because it directly aligns with the definition of phenotype, emphasizing that it is not just about the underlying genetic information but rather how those genetics manifest in physical form.

In contrast, the genetic makeup is what defines the organism's genotype, which is the collection of genes inherited from its parents. Variability of species relates to the diversity seen within and between species, which is a broader concept not limited to individual traits. The dominant allele refers specifically to a type of allele that can mask the expression of a recessive allele, thus influencing phenotype but not representing it in its entirety. The focus on visible traits makes "the physical representation of genetic traits" the key aspect defining phenotype.