Some research suggests that marital satisfaction over a lifetime appears to follow a u-shaped curve; this means that

A U-shaped curve, this means that satisfaction is highest in the early years of a marriage and then again in late adulthood. In the early years of marriage, the couple is still fond of each other but gets to grow tired as time goes by. In late adulthood, satisfaction is high as they reconnect.

f 5 , h

the factors that the economies of the muslim empires prosper were:

1- land trade routes-located between three continents  

2- sea trade routes

trade contributed to the spread of muslim empires, and with that islamic culture led to a growing feeling of internationalism resulted in the transfer of technology, science, and other cultural forms.