What was a significant factor in the growth of cities during the 1920s?

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Explanation:

The factors that caused the growth of cities in America were threefold. First, the Civil War had displaced thousands of soldiers and emancipated Black people, many of whom migrated to the cities in the North. Second, the concentration of industry and banking significantly increased the power of major metropoles. Finally, immigration from Europe inflated the number of urban inhabitants as well. Americans responded to the challenges by initiating the Progressive Movement and advocating for labor laws.

the answers is b.   environments.

powers  are  denied  to the  national governmentin three distinct ways: some  powers, such as the  power  to levy duties on exports or prohibit the freedom of religion, speech, press, or assembly, are expressly  denied  to the  national government  in the  constitution.