Fiverr works just like any other marketplace. Sellers list their services (gigs) and buyers who are interested in these services ask questions and if they are satisfied with answers, purchase them. Fiverr works like a middleman guaranteeing both parties are happy with the end result.
The Cunninghams are a poor farming family in Maycomb. They are hard-working, but are not aware of many social cues, as they spend most of their time working on the farm. Walter Cunningham Sr. is a good man overall, but gets swept into the racism and hive-mindedness of the town.
The Ewells are also a poor family in the area, but do not have a good reputation in Maycomb. They live in a run-down part of town, their children only go to school the first day of the school year each year to sneak their way around the law, and their father is known around town for being a low-life. This proves to be true in the courtroom scene, when we find that Bob Ewell is also an abusive liar.
shark is to fish as crocodile is to reptile
hope that helps
Supporting details can do all of the enlisted options except introduce the main idea. Supporting details are there to support the main idea, so of course they cannot introduce it. They are the result of the main idea, not its creator.