According to Rothenberg, how is difference socially constructed?

the text book is race class and gender in the united states. Atleast 250 word response. MLA or APA citing of references. required reading:

1. Part I Introduction: The Social Construction of Difference: Race, Class, Gender, and Sexuality, Paula Rothenberg, pp. 7-12
2. Imagine a Country, 2012, Holly Sklar, pp. 324-334
3. Domination & Subordination,  Jean Baker Miller, pp. 110-116
4. Oppression, Marilyn Frye, pp. 149-152
5. The Problem of Discrimination, U.S. Commission on Civil Rights, pp. 263-273
6. Defining Racism: "Can We Talk?", Beverly Daniel Tatum, pp. 125-132
7. Constructing Race, Creating White Privilege, Pem Davidson Buck, pp. 33-38
8. White Privilege: Unpacking the Invisible Knapsack, Peggy McIntosh, pp. 175–179
9. Unequal Childhoods: Class, Race, and Family Life, Annette Lareau, pp. 180-188