Which genetic term describes the observable characteristics of an organism?

The term that describes the observable characteristics of an organism is phenotype. The phenotype encompasses all the physical, biochemical, and behavioral traits that can be seen or measured. These can include traits such as height, eye color, and flower color in plants, which are influenced by the underlying genetic makeup, or genotype, of the organism along with environmental factors.

In contrast, genotype refers specifically to the genetic makeup or the specific alleles present in an organism. Alleles are different versions of a gene that may produce different traits, but they do not refer to the characteristics themselves. Gametes are the reproductive cells (sperm and egg) that carry alleles to the next generation, but they are not related to the observable traits of an organism. Thus, phenotype is the term that accurately represents the visual and measurable traits that define an organism's appearance and behavior.