Which river supported the civilization of egypt? what is its significance?

crop rotation kepy different plants in the soil instead of once constintly. when switching out plants you have different nutrients being absorbed at different speeds and different roots growing differently therfore the spoil and water flow have to adapt and carry fresh nutrients to carry the constant changes that were going on in the soil.

i think it was because of how protected egyptian civilization was was which allowed them to evolve without much outside influence.