Which historical experience directly encouraged the spirit of volunteerism in america?

the rejection of the power of the british monarchy 
the divisions between the north and south during the civil war 
settlers moving into territories lacking government with a need to promote the public good
growth of population over many years due to immigration 

the population grew a lot and was making more money

the completion of the erie canal spurred the first great westward movement of american settlers, gave access to the rich land and resources west of the appalachians and made new york the preeminent commercial city in the united states.

what the first or next guy says

no statements but ok.

the statement that best describes the idea of manifest destiny that was used in the 19th century would be that "it was fate that the united states would continue to  expand westward," since people thought the us was "destined" to do so.