Pillard and Bailey discovered that when one fraternal twin is homosexual, the chance of the other being homosexual is about

According to research conducted by Ridley (1999), how could individuals like Adolph Hitler, serial killer Ted Bundy, and Unabomber Timothy McVeigh commit such acts according to the "nature versus nurture" debate?

a) These individuals were born (nature) to commit such horrendous acts. It was in their genetic makeup. b) Their behaviors are the result of the interaction of nature and nurture. c) These individual's behaviors were attributed to "nurture" and influences of their parents. d) These individuals learned to commit these behaviors after staying in long periods of isolation according to

Biff and his twin brother Bernie, were part of a twins study. They were first observed by the researchers when they were 5 years old, and then again later when they were 10 years old. What type of a study were they in?

a) case b) cross-sectional c) longitudinal d) periodical