Answer: The exposition of the story is presented in the lines; "There was once a Parsee living on an uninhabited island in the Red Sea, with a shiny hat, a knife, and a cooking-stove."
Explanation: A narrative exposition is the introduction of a character's background, the environment, or past events that preceded the story. In this tale, the exposition of the story is at the beginning. You learn that a Parsee was living in an uninhabited island and that he had a knife and a cooking stove. This is important later on in the story, since that man bakes cakes, and puts crumbs from previous ones on the Rhino's skin, to then make him rub everywhere and have wrinkles on it.
I think it was to show how Mercutio and Benvolio were laughing and slightly mocking the capulets whilst also adding the idea that they always pick the fights and are the antagonists