What is the earliest known civilizations in the americas and where was it located

Martha participates in a research study in order to receive extra credit for her psychology class. when she arrives in the research office she is given a can of what looks and tastes like beer, but which actually contains no alcohol. in the adjoining room martha's classmate karen is also participating in the study. karen receives a can of alcoholic beer. if the experiment was designed to test the effects of alcohol on concentration, then who is exposed to the independent variable?

Which phrase in the preamble of the constitution means the government should provide peace and order in society.

In a communication, the media needs to be shared between devices