Final answer:
Heterogamous marriages are those between individuals from different social and demographic backgrounds, focused on love and compatibility, unlike endogamous marriages, which occur within the same social group. Polygamous marriages involve more than two spouses, with polygyny being more common than polyandry. Monogamous marriages include same-sex unions, which are legally recognized in many countries.
Step-by-step explanation:
Marriages between individuals who differ in certain specific social and demographic characteristics are referred to as heterogamous marriages. Unlike endogamous marriages, where individuals marry within their social group or class, heterogamous marriages consist of spouses from different social categories. This type of marriage is based on values such as love and compatibility rather than social standing or economics.
In contrast, polygamous marriages involve more than two spouses. Among polygamous arrangements, polygyny is where a man is married to multiple women and is the most common form, whereas polyandry involves a woman being married to multiple men, which is much less common.
Anthropologists also find that monogamy, consisting of the marriage between two adults only, is adapted well to postindustrial societies and includes same-sex marriages in countries where it is legally recognized. The legalization of same-sex marriage has been achieved in many countries, broadening the understanding and acceptance of various forms of monogamous unions.