@Stunner

Thanks a lot for such a detailed answer.

I want to ask another question.

“MUTAWAKKIL, the NERO of the ARAB was responsible of the decline of the Empire”.Comment. (2012)

Is the MUTAWAKKIL in above question is that 10th Caliph of the Abbasid Caliphate (847–861)? if yes, than dont you think that this question is illogical, as in book, there are hardly 2 pages on MUTAWAKKIL. How one will write answer of 20 marks. And i think that MUTAWAKKIL is also not popular or even worth to read ?

Please comment. Thanks in anticipation.