Cathode-ray-tube TVs,with their familiar protruding backsides, may look bulky and primitive next to today's sleek flat-screen models, but they've still got two big advantages: they're cheap, and they're relatively energy efficient. Plasma flat screens, for example, still cost $2,000 or more apiece, and they use up to five times as much electricity as CRTs. They're such energy hogs, in fact, that global adoption of plasma TVs could increase electrical demand noticeably, increasing both the chances of blackouts and the volume of greenhouse gases emitted by power plants.

Select from the choices above to read the entire article.