What is the expostion of the book pop by Gordon Korman?

In the book "Pop" by Gordon Korman, the exposition introduces the main character, a high school football player named Marcus Jordan, who discovers that his estranged grandfather, Charlie Popovich, is a former NFL star. Marcus is initially skeptical about this revelation but eventually forms a bond with his grandfather as they navigate challenges together. The exposition sets the stage for Marcus's personal growth and the rediscovery of his family's history.