The
assignment in SDV applied the problem-solving soft
skill? (You may choose more than one.)

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.        

where's the

it's

answer; they are called (pebbling);