The two goods traded between northern africa and the niger river empires were: gold and silver slaves and salt gold and salt slaves and silver

gold and salt

Explanation:

Gold and salt were the two main products that were traded between Northern Africa and the Niger River Empires. Gold was particularly abundant in the Niger River Empires, and this gave rise to various kingdoms, such as the Ghana empire. Gold was in great demand all over the world. On the other hand, salt was also in demand, but not as currency. Salt was very valued because it allowed food to be preserved.

c. it required that townships set aside land for public schools.