Turner's main argument in "the significance of the frontier in american
history" was that the frontier was significant:

Turner's main argument in "The Significance of the Frontier in American

History" was that the frontier was significant in American history. The purpose of "The Significance of the Frontier in American

History" is to explain not only the significance of the frontier on the development of America and Americans, but also to emphasize that the disappearance of the frontier marks the close of the first major chapter in American history.

theodore roosevelt 26th u.s. president : i admire his energy and passion. he was a fundamentally good man, brilliantly intelligent, possessed of extraordinary will and ability, supremely self-confident, bold, egalitarian, idealistic…. , lord, can we have him back?

you didn't list the options. however, a few communist countries today are: the people's republic of china, north korea, and cuba.