Which term best describes heritable differences among individuals in a population?

• A. Variation
• B. Mutation
• C. Adaptation
• D. Fitness

Answer: (A)

Variation is the term that captures heritable differences among individuals in a population. These differences come from genetic variation passed from parents to offspring, including variants created by mutations and shuffled through recombination during reproduction. This diversity is the raw material natural selection acts on, allowing some variants to be more successful in a given environment and to become more common over generations. While mutations are a source of new variation, and adaptation refers to traits that improve fitness, and fitness describes reproductive success, the broad idea of all inherited differences within the group is best described simply as variation.