What was one major effect of the invasion of poland in 1939

  Great Britain and France declared war on Germany

Explanation:  Germany invaded Poland on September 1, 1939, which officially began the Second World War. Britain and France declared a war on Germany on September 3, 1939, due to their guarantee of the unchanging  of state border of Poland. Later it also resulted in the entry of other states into the war,  there were various political agreements and deceptions.  One of them was the attack of the Nazis on the Soviet Union despite the agreement that existed between them.

monopolies  came to the united states with the colonial administration. the large-scale public works needed to make the new world hospitable to old world immigrants required large companies to carry them out. these companies were granted exclusive contracts for these works by the colonial administrators. even after the american revolution, many of these colonial holdovers still functioned due to the contracts and land

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john maynard keynes developed new economic theories in response to the : b) great depression of the 1930s. his theories are so important that they are known as "keynesianism". in his works he supports the idea of a government with deeper involvement and intervention to end the great depression.