Because adoption studies cannot completely control for the influence of the prenatal or early postnatal environment, animal researchers have tried to get around this problem by using the technique of:

What are the surface traits?

a. they are basic traits that underlie source traits b. they are seen in the outward actions of a person c. they form the core of personality d. they are nearly all inheritable

Which is a common reaction to terrorism?

a. feeling angry b. feeling guilty c. feeling anxious d. all of the above