The Abbasid Caliphate differed from others in that it did not have the same borders and extent as Islam. Particularly, in the west of the Caliphate, there were multiple smaller caliphates that existed in relative peace with them.
The major difference between the protist and the animal kingdom is protists are unicellular protozoans and unicellular & multicellular, but animals are multicellular animals.
The key and obvious differences between the Italian Renaissance and the Northern Renaissance is geography in which Northern Renaissance refers to the happenings in countries that were in Northern Italy, other European countries (Low countries and the Holy Roman Empire).