what is this system?
It  is a system of measurement that succeeded the decimalised system based on the metre introduced in France in the 1790s.
Metric system
is a system of measurement that succeeded the decimalised system based on the metre introduced in France in the 1790s. T
which unit is used to measure mass in the metric system UNANSWERABLE
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Metric system [SEP] Introduction
A metric system is a system of measurement that succeeded the decimalised system based on the metre introduced in France in the 1790s. The historical development of these systems culminated in the definition of the International System of Units (SI), under the oversight of an international standards body. The historical evolution of metric systems has resulted in the recognition of several principles. Each of the fundamental dimensions of nature is expressed by a single base unit of measure. The definition of base units has increasingly been realised from natural principles, rather than by copies of physical artefacts. For quantities derived from the fundamental base units of the system, units derived from the base units are used–e.g., the square metre is the derived unit for area, a quantity derived from length.