Answer
Beginning the story with the dialogue between Rainsford and Whitney contributes to the author's characterization of Rainsford as a brave and adventurous hunter, as he is eager to take on the challenge of hunting in the Amazon. It also establishes a suspenseful and mysterious mood, as the conversation hints at the danger and mystery that Rainsford will soon face. Evidence from the story includes Rainsford's statement that "The world is made up of two classes--the hunters and the huntees" and his eagerness to take on the challenge of hunting in the Amazon.