Which theorists developed a temperament classification system in which most children are considered to be easy, difficult, or slow-to-warm-up?

Chess and Thomas

Explanation:

Chess and Thomas were the psychologists who worked on Temperament inventory. They are both have proposed temperament inventory type:

In these types of temperament inventory Chess and Thomas discuss how much babies adjust. In easy-going babies, around 40% of babies easily adapt and adjust the new situation. On the other hand, a 15 % difficult child adjusts in the new situation. Only 10% slow to warm up the child adjust in the new situation.  

Thus there are different inventories given by a different psychologist.  

the arab empire adopted the muslim religion as their main belief. arabs would influence the people from the territories they invaded towards islam (the muslim belief).

nevertheless, throughout the history of the arab empire, rulers brought intellectual individuals from other religions to their centers of learning. these other foreigners included jews, christians, greeks, persians, and indians.   these resulted in the adoption of important knowledge developed by these cultures by the arabic empire. for example, the works of aristotle were translated from greek to arab and indian scientists brought the numerical concept of "zero" to the arabs.

nowadays, 93% of the arab population is muslim, which at the same time is subdivided in sects including the sunni, zaini, alawi, shia. the remaining 7% is composed mainly of christians.

a would be the answer