What is the most significant cause of ww2 and why

What principle did president truman invoke in sending u. s. troops into south korea without first asking congress to declare war?

What motivated germany to make an alliance with austria-hungary?   a.  fear of aggression from the united states      b.  fear of aggression from france      c.  the desire to invade russia      d.  fear of aggression from england

The maps below show the middle east. which best explains how the green areas depicted in the image on the left are reflected in the population map on the right? populations are greater in fertile areas that are close to freshwater sources, which is why more people live near deserts. populations are greater in fertile areas that are close to freshwater sources, which is why more people live near oceans. populations are greater in fertile areas that are close to freshwater sources, which is why more people live near mountains. populations are greater in fertile areas that are close to freshwater sources, which is why more people live near rivers. plz hurry in test only have 34 mins left