Final answer:
The decline of Baghdad cannot be attributed almost totally to the Seljuks; other factors such as weakening of central authority and invasions by external forces played a role.
Step-by-step explanation:
No, the withering of Baghdad, the capital of the Abbasid Caliphate, in the early eleventh century cannot be attributed almost totally to a new Turkish group known as the Seljuks. While the Seljuks did have an impact on the decline of the Abbasid Caliphate, they were not solely responsible for its downfall. The decline of the Abbasid Caliphate was a complex process involving various factors such as the weakening of central authority, the rise of rival caliphates, and invasions by external forces like the Mongols.