Choose all of the terms that specifically represent international trade barriers. A) embargo
B) quota
C) surplus
D) tariff
E) tax

tariff

quota

embargo

hope this helps.

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.        

answercommunism;