The stock market crash started it all.
Explanation:
The stock market crash of 1929 touched off a chain of events that plunged the United States into its longest, deepest economic crisis of its history. It is far too simplistic to view the stock market crash as the single cause of the Great Depression. ... By 1929, companies had expanded to the bubble point.
After heavy shelling and bombing, Warsaw surrendered to the Germans on September 27, 1939. Britain and France, standing by their guarantee of Poland's border, had declared war on Germany on September 3, 1939. The Soviet Union invaded eastern Poland on September 17, 1939.
Answer: I'm not 100% sure about this one but I think it's D. Satellite imaging allows people to map the extent of forest fires.
