In the years from 1820 to 1860, the United States grew to stretch “from sea to shining sea.” What were some key developments that made this growth possible? What problems resulted from this rapid and massive expansion?

Respuesta :

Answer:

I’m the 1820 they were reachin GB for access and needed help

Explanation:

Answer: I typed the same answer as the other person and noticed it was the same.

so, In 1820 they were reaching GB for access of help.

Explanation:

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