Final answer:
Monogamy is the practice of having one wife or husband, while polygamy refers to having more than one spouse at the same time, with polygyny (one man, multiple women) being the most common form.
Step-by-step explanation:
The practice of having one wife or husband is known as monogamy. Monogamy refers to a marriage consisting of only two adults at a time. Conversely, polygamy is the practice of having more than one spouse simultaneously, which is accepted in various cultures worldwide, especially in northern Africa and east Asia. The most prevalent form of polygamy is polygyny, where one man is married to multiple women. A much rarer form, occurring in about 1 percent of the world's cultures, is polyandry, the marriage of one woman to more than one man at the same time.