In the International System of Units, which unit measures mass?

The International System of Units (SI) designates the kilogram as the base unit of mass. It is a fundamental measurement used worldwide across various scientific and engineering disciplines. The kilogram is defined based on a physical standard, and it is the only SI unit with a prefix (kilo) that is also part of its name.

Grams, while also a unit of mass, are defined as one thousandth of a kilogram. Therefore, while grams are commonly used, particularly in everyday situations, the kilogram serves as the primary unit for mass within the SI framework.

Liters are a measure of volume, primarily used to quantify the space that a substance (typically a liquid) occupies. Newtons, on the other hand, are units of force in the SI system, defined in relation to mass and acceleration. As such, the kilogram is the correct answer for measuring mass within the International System of Units.