The era of the cowboys ended mainly due to what?
Rising cost of transportation
Revolt of homesteaders
Depletion of cattle supplies
Expansion of railways

The alamo, davy crockett, and sam houston are most closely associated with a) the texas war for independence. b) the beginnings of the american civil war. c) the acquisition of the the oregon territory. d) the removal of the indians to lands west of the mississippi.