What is the difference between opposing forces and forces working together?

Which type of evidence would support the author's claim?

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?

What effect did the enclosure acts have on people’s working lives? a. changes brought about by the acts prevented large farmers from taking lands from smaller farmers. b. small farmers could no longer work on common lands and had to move to cities for work. c. peasants started working on enclosed lands and soon became wealthy because of higher wages. d. landowners forced peasants to build roads and bridges as part of the new enclosure laws.