By eight weeks after conception, the brain constitutes ____ the length of the entire embryo

A criterion for obsessive-compulsive disorder is that the symptoms must occupy more than

______. a. 5 hours per week c. 1 hour per day b. 2 hours per day d. 10 hours per week

The most effective preventative efforts for STIs involve _________________________

a. better education of teens about STIs b. increased family communication c. more informed attitudes among the peer network d. simultaneous interventions at all three levels