20 POINTS According to the lesson, what were three major problems facing the Union after the Civil War? Select one of the problems you listed and explain why it could be the most difficult one to solve. Please type it out, thank you.

its many islands, high mountains, and remote peninsulas isolated population centers.

worldwide, 780 million people do not have access to an improved water source. an estimated 2.5 billion people lack access to improved sanitation (more than 35% of the world's population)

ba geologist finds four sedimentary rock she determines that no geologic events have shifted the layers she labeles them a,b,c,dbfrom top to bottom

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