Why is there simplified and traditional chinese?

Traditional chinese was the original version of chinese, but the people wanted an easier way of writing with less brush strokes, so, simplified chinese was born. While simplified Chinese is the more common way of writing, as it is used in China, countries like Taiwan use traditional

the answer wold be b) travel among nations should be regulated by an international organization

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).