Review the paragraph with underlined phrases on pages 3-4 click the underlined phrase in the paragraph that contributes most to the ominous mood; the legend of ithenhiela

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?