How do the monkeys that the group encounters in the hill country serve as a plot element, to advance the story?

While Lahiri stresses the social contrasts between Mr. Kapasi and the Americanized Das family, the most focal clash in the story is the inward clash inside Mr. Kapasi. There is an error between the way he sees himself and the way that he really is. After Mrs. Das demonstrates an enthusiasm for him, Mr. Kapasi starts to fantasize about comparing with her and in the long run building up a private relationship.

The answer is "he was bad enough in all conscience, but the devil himself could not temp him to turn slave-trader. satirical is a synonym for sarcastic. so when the author says that tom walker could not be tempted by the devil he does not literally mean "the devil" but he means that he is too morally upright to become a slave-trader.