The phenotype of an organism is determined by the expression of its genotype, which consists of the inherited genetic information. However, the phenotype is also influenced by environmental factors, leading to variations in physical traits, behaviors, and biochemical properties. The interaction between genotype and environment results in observable characteristics such as size, color, and morphology. Understanding phenotypes is essential in fields like genetics, evolutionary biology, and agriculture, as it helps explain how traits are passed on and how organisms adapt to their environments over time.