What was the main reason ancient civilizations were established along the Nile River?

The river had many resources.

Explanation:

The Nile river had fruit trees that grew along its banks that were used as food, and about every 6 months the river flooded and when it seceded there would be a layer of silt that was perfect for farming. The river also had many fish that ancient people could catch to eat.

5.4%

explanation:

their acceptance rate is 5% percent and the graduation rate is 98%

81 is a composite number.