Answer:
Drought
Step-by-step explanation:
The Ghana Empire was a West African Empire located in what is now southeastern Mauritania and present Mali. The Ghana Empire subsisted on trade, particularly the trans-Saharan trade with salt and gold. The wealth acquired from the trade allowed urban centers to develop. It is unclear why the Ghanian empire declined, as records are sparse. However, conflict with the Almoravid Muslims, depletion of salt mines and and competition with gold mines in the South are all cited as possible causes.