Uncle Jack refuses to listen to Scout's side of the story and presumes her to have behaved improperly. This presumption supports the theme of injustice.
In Mark Twain's "A Cub Pilot", Mr. Bixby, who is the main captain of the steamboat, plays the role of some sort of mentor to young Mark Twain, someone to look up to, because he has has always wanted to become a steamboat pilot. His main teacher, Mr. Brown, is rude and violent to him, while Mr. Bixby is not. He sort of represents wisdom and young Twain's perseverance to become a pilot in chief.
Answer:
wheel and axle ,pulley ,inclined plane,screws ,wedge and lever
