Final answer:
A phenotype is the observable expression of an organism's genetic traits, while the genotype is the actual genetic makeup, including both expressed and non-expressed alleles.
Step-by-step explanation:
A phenotype is the physical and visible expression of a genetic trait. This term describes an individual's observable characteristics, which can include a wide range of traits such as hair color, skin color, height, and build. In contrast, the genotype refers to the genetic makeup of an individual, which includes both physically visible and non-expressed alleles. For instance, in Mendel's hybridization experiments with peas, the phenotypic trait of yellow seed color in F₁ hybrid offspring was visible, even though their genotype also contained the allele for green seeds from the other parent, which was not expressed in the F₁ generation but reappeared in the F₂.