Mr. Frank says this line when they are all fighting.
He is saying that they don't need the Nazis to destroy them. They are destroying themselves by fighting. In this scene, they were fighting over food, which was certainly important -- however, Mr. Frank is saying that the good of all must be considered before individual needs.
Mr. Frank is saying that in order to survive, some sacrifice must be made, and the fighting must be stopped.
Either Jermey or John left HIS books in my car.
Answer:
The element that best demonstrates the central idea of the given panels is the 'teacher's annoyed expression and crossed arms'
Explanation: