Over the past century, the rate of infertility in the United States has ____

A bell-shaped curve that characterizes a large sample of intelligence test scores is a

A) factor analysis. B) normal distribution. C) heritability estimate. D) savant syndrome. E) the g factor.

Brian banged his shin against a desk and grimaced with pain. He quickly bent over and began rubbing his leg where he'd banged it and the pain he was experiencing started to subside a bit. This phenomenon can best be explained by __________

a) the gate-control theory. b) the absolute-threshold theory. c) the opponent-process theory. d) the volley theory of pain control.