Lincoln did not pronounce the abolition of slavery as a goal of the war for all of the following reasons except

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; models;

answer; the people,; the elected officials;