Sassafras root is still used to flavor traditional root beer, although since sassafras was banned by the U.S. Food and Drug Administration because of the carcinogenicity of its constituent safrole, most commercial recipes do not contain sassafras. Some commercial root beers do use a safrole-free sassafras extract.
There are usually 18 holes in a golf course; some have 9 holes or some multiplier of 9 holes. I have played at golf clubs with 9, 18, 27 and 36 holes. However, a standard round of golf at most golf clubs / courses involves 18 holes.
Golf courses are 18 holes because of The Old Course; the R&A's headquarters is just behind the 18th green; Old Tom Morris toiled here, innovating in course maintenance and design; Bobby Jones (and many other greats) won here. The Old Course at St. Andrews is iconic. Although it hasn't always impressed first-time visitors from abroad - Sam Snead thought it was an old, abandoned golf course the first time he laid eyes on it. The 18 photos in this gallery depict all 18 holes, in order, with yardages, hole names and other info.