Define cultural pluralism, History Homework Help

Define "cultural pluralism"  [go back to Olson and Beal, 4th edition, p. 4].  Using examples from the documents/primary sources and the specific historical experiences of the Italians or the Jews, what was more responsible for their attempts to hold onto their customs and cultures -- the way they were treated by the larger American society or their desires to maintain their cultures or a combination of both?  Were the resulting attempts to hold onto their customs and cultures reflective of Olson and Beal's definition of "cultural pluralism?"

AT LEAST 250 WORDS.