If the correlation on a trait were .75 for identical twins, .55 for siblings, .23 for cousins, and .11 for genetically unrelated adopted siblings, one could conclude that

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The correlation is highest for identical twins, who have the same genetic makeup, suggesting that heredity plays a significant role in the trait. However, the correlation is not perfect, indicating that environmental factors also contribute to the trait. The decreasing correlations for siblings, cousins, and adopted siblings suggest that the closer the genetic relationship, the higher the correlation, supporting the idea that heredity is a significant contributor. However, the decreasing correlations also suggest that environmental factors play a role, as they would be more similar for closer genetic relationships. Therefore, the best conclusion is that heredity is a prime contributor to that trait, but environment also plays a role.

If the Correlation on a Trait Were