Silver is a whitish precious metal and has been used since about 4000 BC for various purposes such as money, silverware, jewelry and so on. Silver is measured in troy ounces. A troy ounce is 31.10348 grams.
Food Desert Locator from the USDA. GoodFood World Staff, May 4th, 2011. The official definition of a food desert is a low income census tract where at least a third of the residents are a mile from a supermarket or large grocery store.
The USDA created the food pyramid to encourage a healthy diet, but the USDA also has a mission to encourage agricultural products grown in the US. There can be a LOT of conflict between those two goals. So the food pyramid (ahem, I mean MyPlate) is not simply an objective summary of the available evidence.