How did the Louisiana Purchase change America? Explain 3 positive and one negative influence.

Explanation:

It allowed the expansion the United States, it gave the usa more natural resources, strengthened the country materially and strategically,

negative effects:

there was more land that  needed to explore and to defend. costing more  associated with exploring the land. More money waste protecting this land

the great wall of china worked as a defense for the feudal states of the zhou dynasty to the north. during the warring states period more walls were put up to defend the borders of the different kingdoms. it was semi successful because despite the wall, the mongols eventually conquered china also the great wall provided protection to the economic development and cultural progress, safeguarded the trading routes such as the silk road, and secured transmission of information and transportation. @jayxboof

answer; i believe the answer is (mesopotamia); modern day