Read the passage below, and identify its two central ideas. Then explain how each central idea is backed up by supporting details. Passage:

As the editor of the student newspaper, I'm very concerned about our participation levels for the upcoming school year. By my calculations, five of our 12 members have graduated and another two have switched schools. In addition, in a recent student survey, only 15 percent listed "writing" or "photography" as interests, which are our two greatest needs.

I do have a solution, though. I think that a representative from our club should go around to each of the junior high classrooms and do a short presentation on why students should join the newspaper. This way, students will have a more personal invitation — studies show that people are twice as likely to take part in something when they know someone involved or have been personally asked. Also, I happen to know that both the astronomy club and jazz band have had great success using this classroom-to-classroom approach. In fact, each group nearly doubled its membership by doing so.