Why was the migration to cities in the western United States a preferred choice for African Americans?

Going to the west was preferred because they were promised the ability to buy cheap land, which meant you could build a new life there. By getting a land plot, ex slaves could create farms and sell the crop.

Explanation:

This is what I put. I'm not 100% sure it's right though (the last sentence may not be) but I know the land part is!!

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.