<span>Killed thousands of Indians.</span>
The appropriate answer is b. Mongol tribes invading Muslim lands. The Mongol tribes had been empowered Genghis Khan and as such had become a formidable hoard of conquerors that had seized much of the Eurasian landmass and the ruling Islamic caliphate in the west. The hardships during this period marked the end of the Golden age of Islam. <span />
In 1787, the States responded to the weaknesses of the Articles of Confederation by calling for a Convention.
At that convention, the delegates wrote a new Constitution for the United States
The answers are A for Part A and A and B for Part B.
Hope that helped!