Read the excerpt from "broken chain."

alfonso said over and over that she was too nice to pull a stunt like that. but ernie argued that she lived only two blocks from where those girls had told them to wait, that she was in the same grade, and, the clincher, that she had ponytails. secretly, however, ernie was jealous that his brother, two years younger than himself, might have found a girlfriend.

a theme in this excerpt is expressed by