Which Imaginary line divides the Earth into east and westlatitudes?

prime meridian-

The prime meridian, or 0 degrees longitude, and the International Date Line, 180 degrees longitude, divide the Earth into Eastern and Western hemispheres.

Explanation:

answer; self_ disclosure;

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.