Jonas is throwing an apple back and fourth with Asher when he sees the apple change. Jonas does not know that the apple changed color. This began not only the reader's suspicion that Jonas was different, but also Jonas himself.
The Grand Elder finally gave Jonas his assignment. Jonas's assignment is being the Receiver. He does not yet know what he is going to do or what the job really is. This is important because it gives the reader questions on why he is called the Receiver and who is the Giver.
Jonas, as the receiver, asks the Giver to show his what happens when someone is released. Jonas's dad is releasing the smaller twin that a birth mother had birthed. This scene is important because this gives Jonas the idea that the community is wrong, and it foreshadows what may happen to Gabriel.