Phenotypic traits in biology refer to the observable physical and biochemical characteristics of an organism, which are the result of interactions between its genetic makeup (genotype) and environmental influences. These traits can include things like hair color, height, behavior, and disease susceptibility. Studying phenotypic traits is important in understanding the relationship between genetic variation and specific observable characteristics, as well as how these traits are influenced by environmental factors. By studying phenotypic traits, researchers can gain insights into evolution, genetic inheritance, and the development of various organisms.