Answer:
Characterization is the process by which of representing of persons or creature in a dramatic works of art.
characterization is when the author reveals the personality of a character.
You didn't italize or mark the phrase, but I see one good candidate:
"The circus animal trainer" is in a way another name given to Mervin, a kind of "renaming" him: this is called an appositive phrase, so if this was the phrase appositive phrase is the answer! (also, I don't see the other phrases here).
Grover was bullied because he was different, and his differences made it easy for other kids to bully him. He was scrawny, emotional, cripple (a muscular disease in his legs), and he walked funny.
Grover was an easy target. He was scrawny. He cried when he got frustrated. He must've been held back several grades, because he was the only sixth grader with acne and the start of a wispy beard on his chin. On top of all that, he was crippled. He had a note excusing him from PE for the rest of his life because he had some kind of muscular disease in his legs. He walked funny, like every step hurt him, but don't let that fool you. You should've seen him run when it was enchilada day in the cafeteria.