[求助]OG-17 名词短语中心词

ＯＧ－１７Native American burial sites dating back 5,000 years indicate that the residents of Maine at that time were part of a widespread culture of Algonquian-speaking people.

　Part of a widespread culture of Algonquian-speaking people. 这个名词短语的中心词是什么啊? Residents were part of culture 还是 part of people?请教NN.

         'culture'