The correct answer is B. The americas
The Americas provided raw materials that were taken to Europe. Europeans manufactured goods from these materials and traded them to Africans in exchange for slaves. Slaves were then taken to the Americas to get new raw materials. That's how the triangle worked.
Migration led to the population of the world because human life started in Africa, meaning that for people to inhabit places that are now known as America, Europe, Australia, etc., they had to all migrate out of Africa.
The major challenge that the framers faced when setting out to write the Constitution was to create a document and a system of government that could be inclusive of all of the perspectives and viewpoints of the delegates and states involved in the convention. For fear of more conflict amongst the states it was necessary to work to create a document that would be a grand compromise of the many competing views.
One of the most important was climate changes. As climate changed, nomads had to find new places to migrate to which led to people going to areas that were uninhabited before. Another was the development of agriculture which more or less ended the nomadic way of life when people started settling.
