Which of the following statements about identical twins has been supported by research on genes and environment?

• A. Identical twins are less genetically similar than fraternal twins.
• B. Identical twins always have identical personalities regardless of their environment.
• C. Identical twins raised apart often show remarkable similarities in personality and intelligence.
• D. Environmental factors have no influence on the development of identical twins.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the genetic relationship between identical and fraternal twins. Identical twins come from the same fertilized egg and share 100% of their genes, while fraternal twins come from two different eggs and share about 50% of their genes, similar to regular siblings.
2. Step 2: Recognize that research on identical twins raised apart is crucial because it helps separate the effects of genetics (nature) from environment (nurture). If identical twins raised in different environments show similarities, it suggests a strong genetic influence.
3. Step 3: Review findings from twin studies which show that identical twins raised apart often have remarkable similarities in traits such as personality and intelligence, indicating a significant genetic component.
4. Step 4: Understand that despite genetic similarities, environmental factors still play a role in shaping individuals. Identical twins do not always have identical personalities because environment influences development.
5. Step 5: Conclude that the statement 'Identical twins raised apart often show remarkable similarities in personality and intelligence' is supported by research, while the other statements are incorrect based on genetic and environmental evidence.