meter
The official system of measurements is the SI; it has SEVEN base units.
The metre (meter in the USA) is the base unit of length in the metric system. It is equal to the distance light travels in a vacuum in a time interval of 1/299792458 of a second.
By unit of length and distance and conversion ,we can say that the basic unit of length in the metric system the meter.
Well, in the metric system, the base unit for distance is the meter. If that is the unit to which you refer, then there are 1000 milimeters in one "unit", or meter.
meter meter
The base unit for length is the metre.
If, by 'metric system', you mean the 'SI system', then there is no base unit for volume. The unit for volume is called a 'derived unit', and it is the cubic metre (m3).
The meter is the metric base unit for volume, and the cubic meter is the derived unit.
A second is a SI base unit.
The SI, or metric, base unit for length is the metre.
The 'meter' is the metric unit of any length or distance, no matter what direction.
The base unit of mass is the kilogram.