What new technologies and discoveries affect communication and transportation?

Which best describes the purpose of the south carolina exposition and protest, which was written by john c. calhoun? a) to explain why the south was nullifying the tariff of 1828 b) to describe the ways the tariff of 1828 would southerners c) to persuade northern states to rebel against the federal government d) to ask england for if the south decided to secede from the union

Recently, there has been pressure to loosen clean air standards. use economic arguments to support or oppose this proposed action.

Describe two reasons that cities developed along rivers during the industrial revolution. for full credit, your response must be at least 2 complete sentences.