What is the metric unit of measurement for mass?

The metric unit of measurement for mass is the kilogram. In the International System of Units (SI), the kilogram is the base unit for mass, and it is defined as being equal to the mass of a specific physical prototype. The kilogram is widely used around the world in scientific and everyday contexts to measure weight and mass.

Other options listed do not represent units of mass. Millimeter, decimeter, and centimeter are all units of length. Hence, they measure distance rather than mass, making the kilogram the only correct choice for measuring mass within the metric system. Understanding the distinction between units of mass and units of length is crucial for accurately interpreting measurements in scientific contexts.