PLSS SHELP ME WILL GIVE BRAINLIEST NO LINKS OR I WILL REPORT YOU

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.        

the last day of school because i didn’t have to go to school the next day

answer; u.s senate;