If business is now a global affair, then the export-import business is important, lucrative and necessary. An export-import agent is not a broker --- the agents are lower on the business totem pole.
Most properties are measured using a number and a unit of measurement. The unit of measurement is a standard amount. The number compares the property to that standard amount. This means a tree that is ten times as tall as a meter stick is 10 meters tall.
Length is a measure of one dimension, whereas area is a measure of two dimensions (length squared) and volume is a measure of three dimensions (length cubed). In most systems of measurement, the unit of length is a base unit, from which other units are defined.