If a trait has high heritability, which statement is true?

• A. A large portion of observed variation is due to genetics.
• B. Environmental variation is negligible.
• C. The trait cannot respond to selection.
• D. Random sampling is unnecessary.

Answer: (A)

Heritability measures how much of the variation in a trait, within a given population and environment, is due to genetic differences among individuals. When this value is high, most of the observed differences come from genetics rather than the environment. So the statement that a large portion of the observed variation is due to genetics is the best interpretation.

This doesn’t mean the environment has no effect at all; it just means its contribution to variation is smaller in that context. It also doesn’t imply the trait cannot respond to selection—if there is genetic variation contributing to the trait, selection can lead to a response. And estimating heritability requires proper sampling and study design; saying random sampling is unnecessary isn’t accurate.