Why did the Abbasid dynasty fall?

This is when the Abbasid Empire starts to fall apart; heavy taxation, agrarian disorder, societal mishap, and revolts all play the Abbasid Empire into the hands of the Buyids, a Persian group that captures Baghdad, the capital, and controls the Abbasid for a few years. ... The invasion of the Mongols, who sack Baghdad.

answer; /// i believe that the correct answer is (divison of labor);

b. the passage of the equal rights amendment  

explanation:

this mean that anything that someone else could do they could do