Answer:
At the beginning of the story, Greg Ridley is in a bad mood, and is dreading receiving a lecture from his father, as he knows what the end result will be.
At the end of the story, Greg is anticipating a lecture from his dad once again, but this time, he smiles at the thought of it.
This change occurs because Lemon Brown tells Greg about how he lost his own son, and that the lessons and things a father gives a son should be treasured. Greg realizes this is true, and it shows in his character shift at the end of the story.
It probably has something to do with how the moon goes around the earth due to the gravitational pull and how an apple falls because of gravity as well. Even though the moon isn't falling onto the earth, they are still both following a set of rules that have to do with gravity.
The answer depends on what your teacher believes, but I believe that it would most likely be true.