What is the threat to internal validity that involves physiological processes occurring within the participants that could account for any changes in their behavior

Why was trump elected in the first place? ‍♂️

Greg goes to a high school and observes the way students talk to each other. he makes notes on the words used, the atmosphere of the school and the way the students present themselves to each other. this is an example of a( research method.

In the wake of the civil war, compared to the south the north had sustained very little destruction. had to create a new labor system. had more economic challenges. had to repair damaged property.