The four natural barriers that protected Egypt in each direction would be the sea, rivers, desert, and mountains, although of course now these offer little protection.
The answer for your question is the 3rd answer
They put them in ghettos and tried to starve them at first, before the Final Solution
The correct answer is <span>Louisiana Purchase
Basically, France lost a war with Britain and the United States believed that Britain might ask for the territory in order to come back to the continent. In order to prevent this, they decided to buy the territory from France which doubled the territory of the United States and opened up further passages to the west. Thomas Jefferson was the president who approved of this.</span>