Why was the monroe doctrine was important to american history?

Explanation:

It caused the U.S. and Europe to temporarily hold off on having any wars or quarrels and also set the stage for documents of a similar style.

answer; /// i believe that they became successful farmers; ///////////////

the right answer is the third one: turnpikes went short distances to connect markets. turnpikes, also known as toll roads, were very important for trade and transportation (of people, goods and products) in the 19th century, coinciding with the expansion towards the west. they contributed significantly to the economic development of the united states.