gram
You should clarify what you want to measure about it: its diameter, mass, weight, color, etc. If you want to measure its diameter, that would usually be specified in microns (= micrometers).
Metres
feet
Potatoes are sold by the kilogram.
To measure the mm of an item you would need to use a metric ruler. The metric ruler has cm and mm on it.
you would measure it in kilograms
kilograms.
The weight of the box would be measured in grams.
A scale
Mass is measured in kilograms.
milli-gram
Every country in Europe uses the metric system, meaning they would measure weight in kilograms, grams, etc.
The metric unit for measuring human weight is actually the Newton (N). Newton's are a measure of force and weight is the product of the acceleration of gravity and an objects mass. The metric unit for measuring human mass is the kilogram (kg).
A gram would be an appropriate measure for its mass.
It depends on whether you want to measure mass or weight so your question needs to be more specific.
Grams
the best answer from me you can get is i would have to say measure it by pounds