Which of the following made the twenties “roar”? new inventions government policies end of the war social changes

end of the war

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necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.

a phrase from a poem by ralph waldo emerson about the battle of lexington and concord. emerson's words read, “here once the embattled farmers stood / and fired the shot heard round the world.”