A milligram is a metric unit of mass. It is equal to one-thousandth of a gram and is commonly used in science and medicine to measure small quantities of substances. The metric system, which includes units like grams and liters, is based on powers of ten, making it easy to convert between units.
A milligram is metric.
It is a customary unit.
The opposing systems are imperial and metric, not customary. But, meters are metric.
The pound is NOT a metric unit.
It is customary.
It can be more or less. An once (customary) is bigger than a gram (metric) but a pound (customary) is smaller than a kilogram (metric).
Metric.
Metric.
Metric
A "gran" is a German measurement, it is neither customary or metric. A "gram" is a metric unit.
customary
It is a customary unit.