Florida Biology EOC Practice Test 2026 - Free Biology End-of-Course Practice Questions and Study Guide

A dominant trait is one that will manifest in the organism's phenotype even when only one copy of the allele is present. This means that if an individual has at least one dominant allele, that trait will be expressed regardless of the presence of any recessive alleles.

For example, if an allele for a dominant trait is represented by "A" and an allele for a recessive trait is represented by "a," an individual with either the genotype "AA" or "Aa" will display the dominant trait. This illustrates how dominant traits can overshadow recessive traits and have a definitive influence on the organism's appearance, making this option the correct choice.

The other options do not accurately describe dominant traits. A trait that can only be expressed in homozygous conditions pertains to recessive traits, not dominant traits. The idea that a dominant trait can only appear in the absence of a recessive allele misrepresents the nature of dominance, as dominant traits can be present alongside recessive alleles. Finally, the notion that a dominant trait is less common in a population is misleading; dominant traits can be prevalent or rare, depending on various genetic and environmental factors.