Which of the following is the strongest evidence supporting the belief that differences among people in their IQ scores are related in part to differences in heredity?

A) There is a high positive correlation between the IQ of children and the IQs of their parents.
B) Children adopted by high-IQ parents generally develop higher IQ scores than do children adopted by low-IQ parents.
C) Children generally have approximately the same IQ score at age 8 that they will have in adulthood.
D) There is a high correlation in IQ between identical twins who have been adopted by different parents and reared in different environments.

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Shortie Leprechaun · Accepted Answer

Final Answer : D, Explanation :  The fact that identical twins who have been adopted by different parents and raised in different environments still have a high correlation in their IQ scores provides strong evidence that IQ differences are related in part to differences in heredity. This is because twins share identical genes, so any differences in their IQ must be due to environmental factors. The fact that their IQ scores are still highly correlated despite being raised in different environments suggests that genetic factors play a significant role in determining IQ. While options A, B, and C also provide some evidence for a genetic component to IQ differences, the evidence from option D is considered much stronger.

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