When talking of the ancient cultures, the area between Tigris and Euphrates is referred to as "Mesopotamia" - and I believe that this is the correct answer .
The name actually means "between (meso) the two rivers" - the two rivers were very important for the region as they allowed the irrigation of the land <span />
Hi there! The answer is C. barbarian raids.
Local farmers were unable to feed the Roman population during the fall of the Roman Empire because of barbarian raids. Between the 4th and 5th century, large groups of people entered the Roman Empire, which caused state failure inside the Empire. This period is called the Migration Period and preluded the Middle Ages.
The ocean floor spreading showed that it is possible for landmasses to move.