Answer:
The calendar
Explanation:
The egyptians invented the calendar so that they could know when the Nile would flood. I know I' m very late on this but I just want to help :)
D (Their crops influenced people's diets in many different regions around the world)
There is no opportunity cost. The cell phone encompasses all three of the features sought after.
Americans did not support the way that he was running the country as a “black man” so pretty much some white guys formed a group to asassinate him