What illegal substance, when used by pregnant women, led to an epidemic of thousands of "crack babies"?

Research on the extent to which adult communication helps children correct errors and take the next grammatical step forward shows that such techniques

A) are actually negative in outcome because children become overly frustrated. B) make no demonstrable difference in grammar development. C) are inconclusive in their impact. D) are dramatic in effect across cultures.

Which of the following statements about hormone therapy is true?

A) It lessens the risk of breast cancer if taken for at least four years. B) It is used by approximately 75 percent of postmenopausal women. C) It is highly successful at counteracting hot flashes. D) It has little effect on improving vaginal dryness.