'जुड़वाँ अध्ययन' (twin studies) का मुख्य निष्कर्ष है:

उत्तर: (D) Both heredity and environment contribute to development, but their relative contribution varies — Twin studies: identical twins (100% genes) raised apart still show similarities (heredity influence) but also differences (environment influence). Conclusion: both nature and nurture interact. Heritab...