What is the important role of innate genetic factors and acquired environmental influences on human development? Twin studies have an important role in answering this question. Only environmental impact determinists predict that a pair of twin babies will be completely separated and raised while a pair of irrelevant babies are raised together. In terms of personality and other characteristics, there will never be more similarity between the first two than the latter two. Actual statistics do not support this extreme view, but they do not support another extreme view. The determinism of genetic factors only. What is the best conclusion to draw from the above discussion? ['In order to determine which of the two extreme views is correct, further research is needed.', 'Although it cannot be said that environmental impact plays the sole decisive role in human development, it actually plays the most important role.', 'Both environmental impacts and genetic factors play important roles in human development.', 'Twin studies are unsatisfactory because it draws contradictory conclusions.']