Understanding the different assessments of the social class system in the U.S. What is the center of the dispute between functionalist and conflict theorists

I’m studying for my Sociology class and don’t understand how to answer this. Can you help me study?

According to the text, functionalists and conflict theorists understand the social class system differently. Their respective analyses of class differences, justification for the class system and degree of mobility possible within the system are sharply divergent. How can we understand their radically different assessments of the social class system in the U.S.? What seems to be in the center of the dispute?

APA. 500 words. 2 references minimum.