PROMPT: In Isabel Wilkerson’s book, Caste: The Origins of Our Discontents, 2020, she suggests that America’s entire social structure is an unrecognized “caste” system – primarily based on race. In your study of the last 150 years of American history, do you agree that our American racial caste system is rigid? Have African Americans – and others – been able to progress and make significant strides in social justice especially since the 1960s Civil Rights Movement? Why or why not? Add plenty of historical details to support your thesis. 
Maximum 1000 words, or 8 paragraphs.