What distinguishes phenotype from genotype?

The distinction between phenotype and genotype is fundamental in genetics. The correct answer highlights that phenotype refers to the observable characteristics of an organism, such as physical traits, biochemical properties, and behaviors. These traits are the result of the interaction between the organism's genotype and its environment.

Genotype, on the other hand, describes the specific genetic makeup of an individual, including the alleles it possesses for various traits. Understanding this distinction is crucial because while genotype provides the potential for certain traits, it is the phenotype that is expressed and observed in the organism. This means that different genotypes can sometimes lead to the same phenotype due to environmental influences or genetic interactions, showcasing the complexity of heredity and expression.

The other options misinterpret the roles of genotype and phenotype, mixing their definitions or mistakenly limiting the expression of traits based on genetic combinations. By grasping this key distinction, you'll have a solid foundation for understanding inheritance and the expression of traits in biological organisms.