The two areas that made it possible for the ecosystems to use the trans-saharan trade route was the Desert and the Sahel.
The trans-Saharan trade route extended from North Africa, across the desert to Western Africa.
With Egypt being so close to the Middle East, the trade route usually started there and went across the desert to the Sahel as show in the attached image.
Find out more on the trans-Saharan trade route at https://brainly.com/question/18713948.