Which statement best describes a polygenic trait?

• A. It is determined by a single gene.
• B. It is influenced by environmental factors only.
• C. It is inherited through mitochondrial DNA only.
• D. It is influenced by two or more genes.

Answer: (D)

Polygenic traits come from the combined effects of multiple genes. Each gene adds a small amount to the overall phenotype, so the trait shows continuous variation rather than a simple, discrete category. This is why the best statement is that the trait is influenced by two or more genes—the hallmark of polygenic inheritance. In contrast, a single-gene trait would produce distinct categories, mitochondrial DNA inheritance describes a different, maternally inherited pattern, and while environment can modulate expression, it does not define polygenic inheritance.