Answer:
This chapter deals with the relationships between the siblings. At the same time that Graff is freaking out because of Ender's computerized similarity to Peter, Valentine realizes that there is much of Peter in her as well. Valentine and Peter's actions demonstrate that on earth just as in space it will be the Wiggin children who hold the power. Although they have not yet started to exert real influence, it seems clear that Peter will get what he wants. Peter is scary because his intellect is matched only by his ambition, and there is no doubt that he can manipulate almost everyone. The only question is whether or not Valentine can temper his actions. Although she is going along with him, her motivations are different. Valentine enjoys having power but does not thirst after it the same way that Peter does. She also knows that Peter is right, that things are changing, and that they can make a difference.
The interaction between Valentine and Graff is especially interesting because he makes no attempt to deceive her. He basically makes it clear that she can have some influence on helping Ender even as Graff manipulates her letter for his own use. Graff is the only character in the book so far to see the Wiggin children for what they are—mature minds inside the bodies of children. He treats Valentine as an intellectual equal. The effect that her letter has on Ender is at once tragic and helpful. It destroys for him the only memory that still meant anything to him, but at the same time it angers him. Ender has been in a state of despair, and his anger reaches enough of an emotional peak to move him farther in the mind game than he had ever been. It was only by taking away Ender's most precious posession that Graff could spur earth's savior onward to step outside of the rules again and figure out a way to do the impossible. The sacrifice for Ender was great, and it has made him view Graff and the teachers as the enemy, but Graff's manipulation worked perfectly, for Ender is once again ready for battle.
Explanation:
