Two concepts that have some similarity in the literature on health economics are "variations in medical care" and "demand inducement." Indeed, some people have suggested that demand inducement "explains" variations in medical care. (a) In one or two sentences, what key feature about "demand inducement" distinguishes it from "variations in treatment rates."? (b) What evidence can you use to support the idea that demand inducement DOES NOT account for or "explain" variations in medical practice use