In Roll of Thunder, Hear My Cry, how does the author explore the theme of racism?

At its heart, Roll of Thunder, Hear My Cry is a story about the tragic effects of racism on the black and white citizens of the rural area near Strawberry, Mississippi, during the Depression. Racial segregation is clearly illustrated in the opening chapters. The black children attend a shabby, dismal school in a group of four ill-heated and weather-beaten houses where classrooms are separated by curtains. The crabgrass lawn is forage for the caretaker's cow. The children walk as much as 3-and-a-half hours each way to attend school, often barefoot, wearing faded, patched, threadbare clothing. They're thrilled to receive books, until they realize they've been given the white children's castoffs, texts that are 12 years out of date.

The white children, by contrast, attend Jefferson Davis County School, a long, white building with expansive lawn, flowers, and a large sports field. They study from new books and wear nice clothes to ride the two school buses. The white bus driver takes pleasure in running the black children off the road, forcing them to jump into the briars and weeds and splashing them with mud. The white children, following his lead, laugh and jeer at their black counterparts.

Even worse than the poverty, is the injustice. When Cassie accidentally bumps into Lucille Jane in Strawberry, she's insulted, pushed into the street by a grown man, and forced into a humiliating apology. Her grandmother, Big Ma, is powerless to help her. The entire black community lives under the constant threat of lynching. Eventually, the racism devastates both a good portion of the Logan land and the life of TJ Avery.