According to a study in sociology, the most widely used illegal drug among high school seniors is/are a. marijuana. b. cocaine. c. hallucinogens. d. speed. ((this is a real question i have on my unit test on egenuity xd))

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.        

answer; exploratory;