What effect did the cataracts have on trade between upper and lower egypt?

How do corporate finances, investor expectations and external forces influence stock prices and possibly pose a risk to investors

Which factor contributed to the rise of african empires such as ghana and mali ? a. their creation and involvement in trade networks b. they focused only on agricultural production. c. they didn’t engage in warfare with other nations d. their geographic location protected them from attacks.

Can someone me answer all the questions?