The Tone is achieved through word choice (diction), sentence construction and word order (syntax), and by what the viewpoint character focuses on. The Tone is created or altered by the way the viewpoint character/narrator treats the story problem and other characters, and by the way, he responds to the events surrounding him.
A) To identify the focus of a paragraph.
The purpose of a topic sentence in a paragraph is to let the reader know what the paragraph will be about.
I don't really understand what u r asking but centeral idea is main idea if that's what u r asking...
