the ghana empire created extensive trade networks across the sahara desert, sending out caravans bearing

Salt and Gold

Explanation:

2686-2181 bce-- "egyptian civilization developed along the nile river in large part because the river’s annual flooding ensured reliable, rich soil for growing crops."

1069-664 bce-- "ancient egyptians developed wide-reaching trade networks along the nile, in the red sea, and in the near east."

seeing as no choices were provided, i'll do my best to answer it from knowledge.

job specialization promotes work ethic to the person doing the job. he/she may be strong in the arms and able to lift things, specializing him/her in a job where you lift and carry.