Why is the adventures of huckleberry finn considered an example of realism?

Huckleberry Finn, Mark Twain criticizes his society by making use of satire: presenting its problems in a humorous way. What realists did was to represent events as if they were describing a photograph, depicting exactly things as they saw them. One resource that Mark Twain uses to make his novel feel more real and photographic is a masterful use of dialects and colloquial English. Another resource, is his description of some people's beliefs, even when they sound highly controversial to the rest of the society.He uses a lot of imagery .