Which of the following principles you think is most important to the american system of government and why-limited government, individual rights, or federalism.

The answer is direct and is Limited government. The reason for that is because it allows a nice clearence for individual rights to flourish and expand. Also Limited government decreases federalism and deters it. Hope this can be a good option for you. 

The answer is society was a caste like system with poor whites at the bottom of the white social ladder.

During the paleolithic, hominins grouped together in small societies such as bands, and subsisted by gathering  plants  and fishing, hunting or scavenging wild  animals. the paleolithic is characterized by the use of knapped stone tools, although at the time humans also used  wood  and bone tools.