In the plateau phase, tissues around the vaginal opening become filled with blood and the vaginal opening narrows

Dreams that involve static situations (as opposed to narratives) that are often frightening

occur mainly during __________ sleep. a. REM b. slow-wave c. stage 1 d. stage 2 e. both stage 1 and stage 2

According to the article Going to Pot, about adolescent drug use, a cross-sectional study is one in which

(a) the same people are followed over a long period of time (b) the research groups consist of different individuals where each group represents a different age cohort (c) a large group of people are randomly assigned to research groups (d) research groups consist of people from different socioeconomic status [SES] levels