What river flows north through Egypt that is effected by the elevation of the Ethiopian Highlands?

The Blue Nile.

Explanation:

The Blue Nile is carved into the Ethiopian plateau, which rises at elevations of 2000–3000 m above mean sea level, with several peaks up to 4000 m or more.

abu bakr, was a senior companion and—through his daughter aisha—a father-in-law of the islamic prophet muhammad. abu bakr became the first openly declared muslim outside muhammad's family. abu bakr served as a trusted advisor to muhammad.

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.