The land area is divided geographically by the (two words) .

president thomas jefferson commissioned the expedition shortly after the louisiana purchase in 1803 to explore and to map the newly acquired territory, to find a practical route across the western half of the continent, and to establish an american presence in this territory before britain and other european powers

it is the dominance of   the spanish language and roman catholic region in mexico, french being the official language of several african countries, and the existence of a western-style government in south asian countries

what are the choices?

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.