What term describes an organism's physical appearance or visible traits?

The term that describes an organism's physical appearance or visible traits is phenotype. Phenotype encompasses all observable characteristics, such as morphology, development, biochemical properties, and behavior, which result from the interaction of its genotype (the genetic makeup) with the environment. This means that while genotype refers to the specific alleles an organism possesses, phenotype is the manifestation of those alleles expressed in traits that can be seen or measured.

Understanding phenotype is crucial in fields like genetics and evolutionary biology, as it helps in the study of how specific genetic variations can influence the physical traits of organisms. For instance, variations in phenotype can be observed in traits such as flower color, height, or skin pigmentation, all of which can be influenced by both genetic and environmental factors. Recognizing the difference between genotype and phenotype is essential for studying inheritance patterns and the impact of genetic variation within populations.