For a Z score of +2.0 from a normal distribution with ? = 50 and ?= 10, the original

If the heritability of a particular trait is found to be 60 percent, then by definition the other 40 percent is due to

A) random chance that impacts every organism. B) prenatal environmental influences, such as toxins or viruses. C) the effects of gene mutation. D) differences in the individual's environment.

Positive symptoms, such as hallucinations, result from

a. an imbalance of norepinephrine in the brain. b. underactivity of the mesolimbic system. c. damage to the mesocortical system. d. overactivity of the mesolimbic system. e. overactivity of the mesocortical system.