What are the exposition and rising action in That Was Then, This Is Now?

The exposition is going to be your introduction.  It is going to give background info on main characters.  In That Was Then, This Is Now the reader is introduced to Mark and Bryon.  We learn that Bryon lives with his mom and that Mark is his adopted foster brother.  Mark's parents are dead after having killed each other in a drunken fight.  The reader also learns that Mark and Bryon are best friends, enjoy hanging out in Charlie's bar, and hustling other players at pool.  

The rising action in the story occurs when Bryon and Mark learn that M&M is looking for them.  They find him in trouble and save him from getting beat up by a group of greasers.  That event thematically ties in with Mark and Bryon meeting Mike Chambers.  Mike is in the hospital after having been beat for an offense that he did not commit.  Both of those events focus on violence for the purpose of revenge.  Bryon is starting to question the legitimacy of that attitude, but Mark still thinks it's good.  A wedge is being driven between the two boys, and it continues to widen.  Other rising action contributes to this widening as well, like Angela's hair-cutting incident, for example.  But probably the final rising action before the climax is Mark beginning to sell drugs.  

In That Was Then, This Is Now, what instances constitute the rising action?

Rising action in the book That Was Then, This Is Now begin with the boys' encounter with hippie M&M during which Bryon and Mark save him from being beaten up, which leads to a thematic encounter with a boy in a hospital recovering from a beating. Another rising action occurs at the school dance where Byron and Cathy are the center of attention until Mark is attacked and Bryon vows revenge on Angela for having Mark attacked.
Then Charlie receives a draft notice for the Vietnam war and Bryon is reflective while Mark takes a car to go to his parole meeting relating to his past offense of car theft. M&M, Mark and Byron all have emotional crises and Angela gets a surprise haircut after she passes out from being drunk and Bryon asks Mark to let go of all the getting even for all the attacks. Bryon finds drugs in Mark's possessions and realizes Mark has no sense of right and wrong. Then comes the climax and resolution, which is of a postmodernist sort with no clear remedy for the fragmentation of the characters' lives.