The greek scientist who concluded that the sun is the center of the solar system, and that the earth revolves around the sun, was

not to sure sdi, strategic defense initiative

a social contract.

"a social contract is an agreement between citizens and their leader where the citizens give up certain freedoms in exchange for protection. the constitution of the united states is an example of a social contract."

disease was the number one killer of native peoples. they had had little exposure to the diseases of europe. this led to some villages being almost completely wiped out and some tribes destroyed.