If the Concordance Rate Between Identical Twins Is Less Than

Multiple Choice

If the concordance rate between identical twins is less than 100 %, what does this imply?

A) Concordance rates are difficult for researchers to calculate; a lack of 100% concordance reflects experimental error.
B) Concordance rates are estimates and can be only measured if one of the twins shows the trait.
C) Concordance rates less than 100% reflect environmental effects on the trait.
D) Concordance rates are estimates of genetic influence only.