In deciding upon a unit of measurement, it is possible to pick anything. For example, the average height of a man could possibly have been a unit of measurement. In fact, some of the units used today in English speaking countries are based on such things as the distance from a man’s elbow to the tip of his middle finger, or the weight of a grain of wheat.

Because there have been so many differences in weights and measures used in different countries, an international system has been urged. If one system were to be adopted by all countries of the world, it would probably be the metric system.