When nelson saw betty in the stockroom stuffing her purse with expensive printer cartridges, betty was quick to say, "we've been friends since first grade, so i'm sure you won't say anything about this." betty was using a(n) on nelson?

answer; migrate from a region;

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.