A group of researchers wanted to find whether trait X was primarily verified by genetics or environment. They analyzed the similarity in trait X between pairs of

1) Monozygotic twins raised in same households;
2) Monozygotic twins raised in different households;
3) Dizygotic twins raised in same households; and
4) Dizygotic twins raised in various households.

If trait X was primarily determined by the environment, which group(s) of twins would demonstrate the highest similarity in trait X? Discuss your answer.