Egypt had a very strategic location, if look at the geography of egypt we will notice that it is surrounded by desert from west and east. the location of egypt played a major role in protecting it from foreign invaders, they will have to cross either the desert of Sinaa from the east or the sahara desert from the west by the lybian borders, it was almost a suicide mission to take a whole army through these harsh conditions where the water and food supply are very scarce, egypt had natural borders which kept the land protected from any foreign invasion. The Nile river is the source of life, without it Egypt would have never existed. so think about it this way (no Nile no Egypt no Pharaoh civilization.
i hope that helped, please let me know if you have any questions or you want me to emphasize a detail for you.
good luck; )
