To help control and plan the flooding of the Nile,
Egyptians developed

The flooding of the Nile has been an important natural cycle in Egypt since ancient times. It is celebrated by Egyptians as an annual holiday for two weeks starting August 15, known as Wafaa El-Nil. It is also celebrated in the Coptic Church by ceremonially throwing a martyr's relic into the river, hence the name, The Martyr's Finger. Ancient Egyptians believed that the Nile flooded every year because of Isis's tears of sorrow for her dead husband, Osiris.

Explanation:

b) trade is easy because of the direct line between their major ports. bilateral trade reached 89,6 thousand million.

when your a dog and you need a bone.   go and eat a rabbit