In the significance of the frontier in american history, frederick jackson turner wrote :
“the frontier has gone, and with its going has closed the first period of american history”
how did advocates of expansionism react to turner's frontier thesis?
a. they argued americans should move from rural areas to expand the nation's new frontier--othe cities,
b. they argued congress should enact new protections for america's natural resources to rebuild the frontier
c. they argued americans should seek new lands overseas as a "safety valve" to release popular discontent.
d. they argued americans should turn away from the culture of the american west and embrace european culture