Answer:
Serve as middlemen for trade along the Upper Nile
Step-by-step explanation:
In antiquity, Nubia bordered the Red Sea to the east and the Libyan desert to the west. To the south, it extended to present-day Khartoum in Sudan. There was very little rain in the region, but the peasants used the water from the Nile to irrigate the plantations. The earth was rich in gold and precious stones. The inhabitants of Nubia were black Africans.
Shortly after 3000 BC, Egypt dominated Nubia. Sometime after 2181 BC, immigrants from Libya arrived in Nubia from the west and settled on the banks of the Nile. This location allowed the Nubians to act as intermediaries for trade along the Upper Nile