Unity is important for an effective functioning of a country and for prevention of conflicts: if there was no unity, people could not finish bigger projects that require cooperation with others.
Diversity is important for innovation and creativity: if we were all the same, little would change and sometimes change is for better.
Answer:
Social psychology, according to Ellwood, is “the study of the [individual psychological] origins involved in the development, structure, and functioning of social groups.”
It focuses that the Bills will be made into laws by Congress. Of course, the President has a veto, but Congress has the final say. It also touches on taxes a bit.