Discuss the assimilation, pluralism, and multiculturalism models, and include their historical timelines.

Discuss the assimilation, pluralism, and multiculturalism models, and include their historical timelines.
How is it that certain groups in the United States never given the opportunity to assimilate? Include the following groups in your analysis: Hispanics, African-Americans and others of African descent, Native-Americans, and Asian-Americans.
What model is used today?
Why is the current model significant in terms of access and privilege?