According to the metric system, which unit is used to measure weight?

In the metric system, weight is measured in grams. The gram is a fundamental unit in this system, which is used widely in scientific contexts and provides a consistent framework for quantifying mass. The metric system is based on powers of ten, making it easier to convert between units, such as grams and kilograms.

In contrast, pounds and ounces are units of measurement used in the imperial system, not the metric system. Liters, while also a metric unit, measure volume rather than weight. Therefore, grams are the correct choice as they directly relate to weight measurement in the metric system.