Why was the us able to stay out of the war for so long? why did they want to stay out of the war?

If you mean WW2, its because America wanted isolationism and didn't want to fight in the war.  They were able to stay out of it for as long as they did because they didn't take sides.

the correct answer is a) egypt and china.

egypt and china are two of the world’s oldest civilizations known by man. both ancient empires have left a great historic and cultural legacy to the world through archeology. both civilzations developed complex social relations, had deep religious beliefs, had dominion of agriculture and left writing records to understand their customs and culture.

among the requirements to consider a civilization, we find urbanization, writing records, a place of residence, agriculture methods, technological specialization, means of transportation, currency, population density, social stratification, and political integration.