You only get one question, so I'll address the first. The relationship between these two changes as Lord of the Flies progresses. Initially, Ralph is not particularly interested in Piggy in any way. In fact, under circumstances in which you'd expect them to work together and cooperate, Ralph is perfectly willing to walk away from Piggy. Ralph does his best to ignore him; once the other boys arrive, he is quick to get a laugh at Piggy's expense by announcing the name Piggy hates. Piggy has always needed Ralph; he just has too much going against him to find friendship among the other boys. Ralph, on the other hand, doesn't need Piggy. As time goes on, though, Ralph comes to recognize his need for Piggy's intellect. Together, they unite against the hunters and the slow move into uncivilized, disorganized, improper behavior. Piggy forgives Ralph, and Ralph gains a new appreciation for Piggy. Towards the end, Piggy is scared, really scared. He knows that, if something happens to Ralph, Jack would love nothing more than to get rid of him. Their final scene together is poignant, as Piggy blindly clings to Ralph as he strives to assert himself and the rules of civility upon Jack and his fellow savages. To no avail. Once Piggy is gone, Ralph is in a purely physical battle for his life.