Although these marital circumstances may have existed for quite some time among early humans, there are a number of reasons why neither polygamy nor polyandry could have survived as universal or general practices.
For one thing, some societies practiced infanticide, killing primarily female infants, and creating a scarcity of women.
Population density in the Nile Valley is one of the highest in the world.
The country occupies approximately 387,000 square miles (1 million square kilometers) in north-eastern Africa.
This can be a virtual formality, or it can be the subject of fierce negotiations, often spread out over months.
Upper (southern) Egypt and Lower (northern) Egypt were joined by the King Menes in the third millennium .