people could now see more of the world without leaving their couch
The myth of the Middle Ages as a "dark age" does not lie in the fact that things declined markedly after the fall of Rome—they did. The Middle Ages is known as a"dark age", imagine how life was in that time . It was basically a completely chaos , things got better though ("the renaissance ").
One reason: Plowing large areas of land
A few more reasons: poor farming practices, farmers would loosen up the soil, and the land was deforested, making it loose the roots that held the soil in place.
The answer is U.S President. Hope this helps
The main world leaders at the time were
Hitler - Germany
Franklin D. Roosevelt - USA
Mussolini - italy
Churchill - Britain
stalin- russia