Only one color, but not one size, Stuck at the bottom, yet easily flies. Present in sun, but not in rain, Doing no harm, and feeling no pain. What is it?

The answer is a shadow :3

well, number 1, the 1920s was not economically prosperous until the start of the lend-lease act, which employed large amounts of people in producing equipment for the allies.

b. world war ii is your answer, because wwi had already ended at 1918, and the cold war was after 1945.

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