One of history's first true super powers, the Persian Empire stretched from the borders of India down through Egypt and up to the northern borders of Greece. But Persia's rule as a dominant empire would finally be brought to an end by a brilliant military and political strategist, Alexander the Great.
Option 'B' = changes in climate, had the greatest impact on pre-historic man.
Changes on the weather forced men to move periodically or cyclically, usually returning to their original location at various times. When they moved to colder climates, they would make clothing out of animal skins, to protect themselves. When the nomads learned how to plant, they didn't need to search for other places anymore.
Negative environmental impacts from unsustainable farming practices include: Land conversion & habitat loss. Wasteful water consumption. Soil erosion and degradation.
The fastest way to communicate across continents in the 1500s was by ship. If you wanted to bring a certain message across a continent than there was no faster way than actually sending it on a ship and waiting for the ship to arrive safely to the other continent.
