The Purpose of Using Twins as a Source of Data

The purpose of using twins as a source of data in personality studies is to

A) show that nature is more powerful than nurture in the development of personality.
B) show that nurture is more powerful than nature in the development of personality.
C) study the effects that both nature and nurture have in the development of personality.
D) concentrate only on nature in the development of personality.
E) concentrate only on nurture in the development of personality.