Which American philosophy most contributed to the "closing" of the Western frontier?

What event caused france and napoleon to want to get rid of its louisiana territory in north america? a) civil war b) seven years war c) slave revolt in haiti d) the french and indian war

What is the relation between the hover dam and the gold rush

Brainliest asap!me : ) has anyone read the poem, no, love is not dead? ? i have a question about it .. : )