What were the two names of the rivers that were in southwest asia

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; early greeks were econimically stagnant and cut off from other near eastern civilizations;