Jesse is attending college in a city far away from home where he does not know anyone. according to the principle of proximity, jesse will be most likely to make friends with:

If the scenario is based on the principal of proximity, Jesse will most likely to make friends with his roommate because his roommate will be the only person that he could get close to and be associated to because he is far away from home and his roommate is the only person that he could get along or connect to.

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.        

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.