Oligopoly and Advertising

Read the paragraph “Oligopoly and Advertising” 
Provide a short description of an oligopolistic market.
Explain why the advertising is a form of a non-price competition.
Check positive and negative effects of advertising in the Oligopolistic Market discussed in this paragraph.
Select four samples of commercials (use the Youtube site) that can illustrate positive effects of advertising (the first two commercials), and negative effects (the other two commercials). Provide some arguments explaining your choice.