What are the social problems in the novel "To Kill a Mockingbird" and what is the relevance of the said problems in 20th century America?explain...

I don't know if there is enough space to address all 7 problems, but I will try to address some.  Poverty is seen in the book in the lives of some characters: the Cunninghams and the Ewells, for instance. Injustice is seen in examples in many places and to various degrees in the story.  The conviction of Tom is injustice at its highest, but the treatment of blacks in general is also an injustice.  A minor example is the way Scout's teacher chastises her for being able to read.  There were very clear lines of racial segregation in the book, and in society in the 1930's society of southern Alabama.  Blacks and whites did not intermingle socially nor geographically.  Discrimination is one of the major themes of the book.  Tom is discriminated against: he's convicted simply because he is black despite the overwhelming evidence of his innocense.  The jury is all men because women were discriminated against.  Crime and violence is seen in the abuse of Mayella which was both criminal and violent.  The vigilante group's attempt to lynch Tom is criminal and violent.  Bob Ewell's attack on Scout and Jem is another major example.  Child abuse is primarily shown in how Boo Radley was treated by his father. The way his father shut him away was nothing but abuse.  Bob Ewell's neglect of his children was abuse, too.  Mental illness is mostly seen in the character of Boo Radley due to his father's treatment of him.