what do historians call a relationship in which one event or variable
contributes to the occurrence of another?

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.

the adoption by russian princes of the mongols' diplomatic rituals

men and women were able to be citizens, but women did not have all of the rights of men including voting and holding office. slaves could be if they were freed.