Question number 16-19 based on the passage below.

    According to the latest New York Times poll, most Americans are troubled by performance-enhancing drugs, which they believe are widely used by the nation's athletes. The public believes that professional athletes in major American sports leagues use steroids to a greater degree than American Olympic athletes do. But the prospect of achievement through illicit means in the Winter and Summer Olympics is more troubling. Also, younger Americans are much less troubled by drug use in sports and believe it to be more widespread than do Americans age 30 and above. After recent revelations about the use of performance-enhancing drugs in football. baseball, and track-and-field, 43 percent of those polled said they believe that at least half of professional athletes in the United States use steroids. In comparison, 18 percent of those surveyed said they believe that at least half of American Olympic athletes use banned performance-enhancing substances. While 61 percent of Americans said they were bothered by the use of steroids among professional athletes. 75 percent said they were concerned about the use of performance enhancing drugs among Olympic athletes. This response seem to be based partly on the ideal that American Olympic spoils are purer than professional sports, and on the widely held belief that Olympic athletes are still amateurs. "The Olympics are pure and clean," Jason Mannino, 32, a tax assessor, said. "We want these kids to be all on the same playing field. A lot of these kids are trying to make a name for themselves purely on their athletic ability, and they are not getting high-dollar contracts to perform. They are performing out of pride for the country and out of pride for getting a gold medal." In fact, the Olympics have been open to professionals since the late 1980's. And most of the drug scandals in recent years have involved sports related to the Olympics.

How does the first sentence relate to the other sentences in the passage?