Final answer:
The practice of being married to one person at a time is known as monogamy. It is the most prevalent form of marriage in many countries, contrasting with polygamy, which includes polygyny and polyandry, and is more common in some societies in Africa and Asia.
Step-by-step explanation:
The practice or state of being married to one person at a time is monogamy. This marital practice is common in the United States and many other countries, particularly in postindustrial societies, where the formation of smaller, mobile family units is often necessary. On the other hand, polygamy refers to being married to more than one person at the same time and is generally divided into two subsets: polygyny, where one man marries multiple women, and polyandry, a far less common arrangement where one woman marries multiple men. Polygyny is frequently practiced in societies in northern Africa and east Asia and can be considered advantageous in terms of labor force maximization and kinship connections.
Conversely, polyandry occurs in only about 1 percent of the world's cultures. While polygamy can be seen as beneficial in certain contexts, monogamy remains the dominant marital model in many parts of the world, adapting well to the requirements of mobile societies and smaller family units, as seen in postindustrial nations.