Multiple choice

The fact that fraternal twins are more similar in intelligence than ordinary siblings suggests the importance of

  1. common hereditary factors

  2. common environmental factors

  3. genetic effects

  4. effects of intrauterine environment
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Fraternal twins share the same genetic relatedness (50%) as ordinary siblings, yet they show greater similarity in intelligence. This indicates that factors beyond genetics contribute to intelligence - specifically, the shared environment they experience both in the womb and growing up together. Common environmental factors like prenatal conditions, family upbringing, and similar life experiences play a crucial role.

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