Answer:
(In secret, Hitler and Stalin had signed an agreement dividing up Poland between the two powers.) On September 3, 1939, Britain declared war on Germany. This marks the beginning of World War II in Europe. ... After Pearl Harbor, in December, America would become directly involved in aiding the British in Europe.
Explanation:
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"B. The improvements in productivity in early agricultural societies enabled more complex societies to develop" is the best option. This improvement in productivity mostly came from the division of labor, which allowed people to do things other than farm.
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