The major reason for the persistence of the american two-party system
a. that there are naturally only two sides to political disputes.
b. regional conflict.
c. the existence of single-member election districts.
d. the existence of state laws prohibiting the placement of a third major party on the ballot.
e. proportional representation.

The development of simple stone tools by early hominids led to the ability to procure meat more efficiently. this in turn led to the change in diet that included larger amounts of protein. many scholars believe that this shift in diet was a significant part of how our ancient ancestors adapted so quickly to a varied set of environments, and thus were able to begin cultural development. this demonstrates the intimate connection between