What does phenotype measure in an organism?

Phenotype refers to the observable physical and physiological traits of an organism, which result from the interaction of its genetic makeup (genotype) and the environment. This encompasses attributes such as size, shape, color, and other measurable features that can be examined directly. The phenotype provides a valuable understanding of how genes manifest in observable traits, allowing researchers to study the influence of genetics and environmental factors on living organisms.

In contrast, the genetic code pertains specifically to the sequence of nucleotides in an organism's DNA, which is not what phenotypes measure. Potential genetic variations concern alleles and genetic diversity but do not directly represent observable traits. Lastly, the number of genes present refers to the organism's genetic content rather than the expression of that genetic information through traits.