I would say that the main purpose of the European Union is to strengthen the economy of the member states by merging their economies and by introducing one stronger, common economy - a stronger economy for the states means a better comfort of life in those states.
Yet, there was one way for Union forces to move into Confederate territory that ended up being a crucial part of the Civil War. The key was rivers, which served as avenues of invasion into the South. And, of course, what was the biggest and most important river for subduing the Confederacy? The Mississippi.
Answer:
Rotating Levers make a(n) INCLINED PLANE
They had been hunting mammoths. They had followed them from Asia to North America.