Which term refers to the physical expression of the genes for a trait by an individual?

The term that refers to the physical expression of the genes for a trait by an individual is phenotype. Phenotype encompasses all observable characteristics, such as physical appearance, behavior, biochemical properties, and more, that result from the interaction of an individual's genotype with the environment. Essentially, the phenotype is the manifestation of the genetic information coded in the individual's genes.

For example, if an individual has a genotype that includes alleles for eye color, the resulting color of the eyes is part of the phenotype. This clear distinction is important in genetics as it allows for the understanding of how different traits can be expressed depending on both genetic and environmental factors.

In contrast, genotype refers specifically to the genetic constitution of an individual, which may not always be observable. Pangenesis is an outdated hypothesis regarding inheritance that proposed that all parts of the body contribute to reproductive cells. Dihybrid refers to a type of genetic cross that examines two traits at the same time, rather than focusing on their expression.