What civilization does the United States base much of it's government systems on?

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.

this headline suggests that midterm congressional   elections are at the corner and trump administration wants to activate his base by vowing to clamp down on immigrants and immigration as trump had said during his election campaign around two years ago. when a baby is born in usa, the baby becomes citizen of usa for 85 years and trump wants to end this rule of birthright citizenship to control illegal immigration and this what he said in an interview""we’re the only country in the world where a person comes in and has a baby, and the baby is essentially a citizen of the united states for 85 years, with all of those benefits,” "

the period of human evolution has coincided with environmental change, including ('hominin' refers to any bipedal species closely related to humans – that is, on how do we know earth's climate has changed? a map showing dates and locations of prehistoric archeological sites and migration routes from africa into.