What effect has mass media had on obesity in the united states a. television commercials and programs have promoted increased acceptance of obesity b. public service announcements have halted the increase in obesity c. educational documentaries have caused obesity in the united states to fall d. advertisments for unhealthy foods have encouraged obesity

Martha participates in a research study in order to receive extra credit for her psychology class. when she arrives in the research office she is given a can of what looks and tastes like beer, but which actually contains no alcohol. in the adjoining room martha's classmate karen is also participating in the study. karen receives a can of alcoholic beer. if the experiment was designed to test the effects of alcohol on concentration, then who is exposed to the independent variable?