The metric system is the official system for all nations of the world.
Explanation:
To make measures, it is necessary to have a set of standardized magnitudes to compare things we want to measure. This set of standardized magnitudes is called a unit system.
The metric system is a decimalized system of measurement which has meters and grams as a basic measurement unit. The metric system is the most used in the world, and also, is the official system for all nations of the world.