What geographic feature brought life to egypt and allowed it to thrive?

the fact that the river Nile flooded every year was one.

this is because with the flooding, the river brought many nutrients to the soil, and made it possible for the Egyptians to farm on the desert.

also because they were surrounded by deserts made it safe from invasions, as the only place for an invasion to happen was the straits of Sinai, but that was heavily defended.

hope it's usefull