What exactly does your question mean??
Antecedent of a pronoun is a word that the pronoun refers to, or replaces. So, in this sentence, we are looking for the antecedent of the pronoun IT. The pronoun IT replaces the noun Chicago, which means that the word Chicago is the antecedent of the pronoun IT.
IT provides the best opportunity, meaning that Chicago does that.
Answer and Explanation: The statement "If you know your pappy did something, you know you can do something too." was made in a bid to show Greg that through hard work, anything in life can be accomplished. This is very significant to Greg because his father was already an accomplished postal worker. And by the statement, Lemon Brown means that his son Jesse was very proud that his father was a famous Blues player, and in relation to this also that he could do anything also that he set his mind to. That would be a way of sharing his successes with his son.