Typically, you will use Meters.
You can measure them with Meter-sticks.
Length is measured in meters in the metric system.
There is only one metric system. Centimetre.
Centimeters
the base unit of length is the metre.
everyone that doesnt live in the United States dont use it
Millimetres
Centimetre
a millimeter
In the English system, probably inches. In the metric system, probably centimetres.
meters
Metres.
Micron