How incient egypt isolated from other cultures by nature borders

On one side it had the Nile which was difficult to cross if the Egyptians didn't want people to cross it. On two sides there was a desert and one the north there was the sea. If Egypt wanted to isolate itself or be defensive in a war it had no problems doing so. It could easily restrict access of foreign cultures.

They made a checks and balance system to equal power within the branches. the "check" meant that one branch would watch one branch and "balance" them if they were too powerful. if you want more info on this, i would just google checks and balance system.