Characteristic traits that are observable are referred to as what?

Observable traits, often described as phenotype, encompass all the characteristics that can be seen or measured in an organism. This includes visible features such as color, shape, and size, as well as more complex attributes like behavior. The phenotype is the result of the interaction between an organism's genetic makeup (genotype) and its environment.

In contrast, the other options do not describe observable traits. The genotype refers to the underlying genetic information that contributes to the phenotype but isn't directly visible itself. Alleles are different forms of a gene that may exist in the genotype, but they are not observable traits per se. Haplotypes refer to a group of genes inherited together from a single parent, providing insights into genetic variation but not specifically the observable characteristics of the organism.

Thus, when looking to identify characteristic traits that are observable, the term phenotype is the most accurate and relevant choice.