The opportunity cost of a decision can be examined by using a
a. production possibilities graph. c. global trade-off grid.
b. factors of production chart. d. graph of increasing costs.

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?