What term describes the degree to which a trait is shared by two or more individuals or groups?

• A. Genetic similarities
• B. Concordance rate
• C. Heritability
• D. Phenotype

Answer: (B)

Concordance rate describes the degree to which a trait is shared by two or more individuals or groups. In twin research, it measures the proportion of twin pairs in which both twins display the trait. A higher concordance rate in identical twins than in fraternal twins indicates a stronger genetic influence on the trait. Genetic similarities is a broad idea about how alike two individuals’ genes are, not a direct measure of trait sharing. Heritability is a population-level statistic about how much of the variation in a trait is due to genetics, not the actual sharing between individuals. Phenotype is the observable trait itself, not the extent to which it is shared.