Answer:
See the answer below
Step-by-step explanation:
Genotype refers to the genetic make-up of an organism while phenotype refers to the physical appearance of an organism.
What characterized the distinction between genotype and phenotype was the discovery of the gene as a dictator of physical appearance. In order words, the distinction between genotype and phenotype was made possible only when gene and self-replicating DNA were discovered and the fact that the gene is a factor that determines how organisms look.