Your answer is gentle souls are often disguised by rough exteriors. The others do not cover the overall theme of the book. Yes some rich and poor kids do not get along, but that is not an overall lesson. Also how often did they walk home alone. The story does not revolve around that. Last, Cherry was not a main character, she was not a main part of the plot. So your answer is once again the first one, it goes with the overall plot of the story.
General adaption syndrome is the different types of responses you body goes through when you are stressed.
Where’s the question? There’s no context, so I can’t really help you with this.
The answer is buy as it means purchase while by is a preposition
