Kilograms are the most appropriate.
The same unit as you use to measure any mass. The SI unit for mass is the kilogram.
You would use the unit of measure called "kilograms" to measure the mass of an elephant.
You Use Atomic Mass Number
mass
The international (SI) unit for mass is the kilogram.
The base unit of mass is the kilogram.
Weighing balance is used to measure mass. The metric unit is kilograms.
Grams
Milligram: to measure its mass.
It depends on what characteristic you want to measure! Its mass, its height, the amount of body fat, the fineness of its fleece?
We use grams (g) as the unit of measurement to measure mass on a triple beam balance.
You would use the metric unit "kilograms" to measure the mass of a wardrobe.