Who is the antagonist?My teacher says there is only one antagonist.

Often when we are questioned about an antagonist in a story or novel we want to know which character is the antagonist.  In "A Long Way From Chicago," the antagonist isn't a person, or character.  In this novel Peck has created the antagonist of Injustice.  Every summer Joey and Mary Alice Dowdel go to a small town and visit their paternal grandmother.  Grandmother Dowdel believed strongly in justice and throughout the story, if she observed an injustice she did her best to straighten it out.  It didn't matter if it was a careless newspaper man, the rough and mean Cowgill boys, the insensitive banker, Mr. Weidenbach, the abusive mother Ms. Eubanks, the sheriff who ran off people he didn't want to deal with, or the prejudice narrow-minded towns people, Grandma Dowdel found a way to enforce her own type of justice.  The depression era story is full of injustices and Grandma Dowdel's attempts to right the wrongs of a most persistent antagonist named injustice.