The First Major Study of Separated Twins Was Done in 1937

Multiple Choice

The first major study of separated twins was done in 1937 by a biologist,a psychologist,and a statistician. Which of the following is true about their study?

A) There was a positive correlation between the twins' IQ, indicating a significant role for heredity.
B) Those twin pairs who had been most completely separated and reared in different environments showed the greatest IQ differences, indicating a significant role for environment.
C) It was difficult to find identical twin pairs who had been fully separated.
D) all of the above