answer for the 1st question :
Because they had a common language and coinage and they set up bureaucracy.
answer for the 2nd question :
the group called ABBASID caused the umayyads to lose support of many people in the empire.
answer fir the 3rd question :
beacause they built a strong standing army and moved the capital to baghdad.
answer for the 4th question :
because of the developments of science and philosophy and all aspects of life in addition to maintaining equal human rights.
answer for the 5th question :
because some abvasids rulers were fond of easy living and people were hating the abbasids rulers alot .
answer for the 6th question :
the create a long unified muslim kingdom with Cardoba as its capital in spain .
answer for 7th question :
because it had 250,000 population and 3000 mosques in it thats why it was a great city.
hope it helps
