What is the difference between line structure and line-and-staff structure?

Advertisers are usually very conscious of their audience. choose an issue of a popular magazine such as time, sports illustrated, vanity fair, rolling stone, or the like. from that issue select three advertisements to analyze. try to determine the audience being appealed to in each advertisement and analyze the appeals used to persuade buyers. how might the appeals differ is the ads were designed to persuade a different audience.