Answer
a. phenotype
Work Step by Step
An organism's observable traits, such as its physical appearance or characteristics, constitute its phenotype. This includes traits like height, color, behavior, and other externally visible features. On the other hand, genotype (option c) refers to the genetic makeup of an organism, which may or may not be directly observable. Variation (option b) refers to the differences that exist among individuals of the same species. Pedigree (option d) refers to the record of descent of an animal, showing it to be purebred or of a particular lineage.
