Which of the following describes a situation where one trait is fully expressed over another?

The correct choice refers to complete dominance, which occurs when one allele exerts a dominating effect over another allele at the same gene locus, leading to the full expression of that dominant trait while the recessive trait is completely masked. In this scenario, individuals carrying at least one copy of the dominant allele will display the dominant phenotype.

In contrast, incomplete dominance involves a blending of the traits, where neither allele is completely dominant, resulting in a phenotype that is a mix of both parental traits. Codominance refers to a situation where both alleles in a heterozygous individual express themselves fully and independently, resulting in a phenotype that shows both traits simultaneously. Pleiotropy describes a single gene affecting multiple traits, rather than one trait overshadowing another.

Understanding these concepts helps clarify the different genetic interactions and expressions of traits in offspring.