What are the traits bigger exhibited that made him subject to racism

The protagonist of the novel, Bigger Thomas is twenty years old, living in one of the many slum apartments of Chicago's predominantly-black South Side. The rough conditions of South Side life are dramatized at the beginning of the novel when Bigger is roused awake by his mother and younger siblings so that he might kill a yellow-fanged rat. Bigger's anger and pride alternate to determine much of the novel's beginning. Bigger feels forever trapt in poverty simply because he is black. This frustration builds in his mind.