What was the main cause of the islamic world's hardships during the thirteenth century?
a. western europeans invading muslim lands
b. mongol tribes invading muslim lands
c. dissension between rival factions of islam
d. famine and diseases introduced from africa

The correct answer in this case is B - Mongol tribes invading Muslim lands.

In the thirteenth century (1200-1300), Mongols were sweeping around Asia, the Middle east, and Europe as well. In the area of the Middle east, muslims were also present when the Mongols came and conquered these lands :)

Your answer is 2 because you do keep change flip when you divide fractions