What was the meaning of the domino theory? a. political decisions have to be built slowly, like a game of dominoes. b. international politics is a game, and there are always winners and losers. c. if one country in a region became communist, others would quickly follow. d. few countries would really be interested in communism if they knew what it was like.

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?