Final answer:
The term 'dominant trait' refers to the observable characteristic or phenotype that is expressed whether an organism has one or two copies of the gene. The dominant trait overshadows the recessive trait unless two recessive alleles are present.
Step-by-step explanation:
The term you're looking for is the dominant trait. This refers to a characteristic that is visible in an organism, regardless of whether the organism has one or two copies of the gene that produces the trait. In genetic terms, the phenotype is the set of observable characteristics of an organism, such as its physical form and structure, resulting from the interaction of its genetic makeup and its environment. For example, the ability to roll one’s tongue is a dominant trait. If an individual has one allele for tongue-rolling (the dominant trait) and one allele for non-tongue-rolling (the recessive trait), they will still be able to roll their tongue because the dominant trait 'wins out' in the phenotype.
On the other hand, a recessive trait is only observable when two recessive alleles for the same characteristic are present. For instance, having blue eyes is typically a recessive trait, so the phenotype of blue eyes is only seen in individuals who have two copies of the allele for blue eyes. The Principle of Dominance, which was formulated by Gregor Mendel, helps to explain how such traits are inherited and expressed in organisms.