Comparing and Contrasting Marriage Rates of the Past with Those

Comparing and contrasting marriage rates of the past with those of the present,anthropologists found that earlier marriages did not last any longer than marriages today.What are some of the reasons for this? If past and present marriage rates do not differ significantly,do the proportion of children raised in single-parent households differ between past and present? Why or why not? How might shorter marriages and single-parent households affect kinship within a society? What other elements may contribute to shorter marriages and single-parent households today,and how do they differ from elements that likely contributed to shorter marriages and single-parent households in the past? Why would anthropologists be interested in researching topics such as shorter marriages and single-parent households?