The formation ,maintenance ,and dissolution of the family are in

The formation ,maintenance ,and dissolution of the family are in
large part a function of the relative balance between the benefits
and costs of marriage.
请问 are in large part a function of ...
是什么意思? 结构是怎样的 呢?
重要的是它的结构 谢谢比如谁修饰谁
尤其是 标题中的内容