It has become more advanced
Answer:
The narrator has hidden the heart of his victim under the floor. Eventually, the police come and investigate the house and, although the narrator tries to stay calm, he suddenly starts hearing the heart beating, getting louder every time, which leads him to confess his crime.
Answer:
I think it is the first option
Mark Twain uses humor and character development as a portraying theme in his books. Much of his humor is the tricks and mischief that the children in his book create. This humor shows the children being childish and a little bit foolish as well. As the story progresses, the characters begin to loose some of that foolishness and grow up. This is after they are faced with conflict and must make adult decisions.