What is the great “myth” that is commonly held in north america regarding the reason for the establishment of a taboo against first-cousin marriage in the united states?

 The correct answer is : The myth is that a greater number of birth defects would be caused.

Explanation:  Nancy Thornhill conducted a sample study of 129 societies where she discovered that the most common incest taboo was among cousins. Massachusetts Governor Briggs delegated a commission to study "idiots" in the state and one of the factors responsible for idiocy is cousin marriage, also a study between deaf and mute in Kentucky yielded the same results, adding blindness.

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.