A very good reason is that postal rates are based on their mass - measured in grams. You can measure the mass in widgets and convert to the units used by the postal service, if you so wish.
gram is the unit for mass, out of your choices.
milliNewtons. A gram or kilogram is a measure of mass, not weight.
use a triple beam balance
The weight unit to use is gram (gramme).
To find the gram molecular mass of the compound, you can use the formula: mass = moles × gram molecular mass. Given that 5 moles of the compound have a mass of 100 grams, you can rearrange the formula to find the gram molecular mass: gram molecular mass = mass / moles. Thus, gram molecular mass = 100 grams / 5 moles = 20 grams per mole.
paper clips do not weigh much, perhaps a gram each, so 10 weigh about 10 grams, so you would use grams, not kilograms, since 1 kg = 1000 grams
Gram, g
A gram.
gram (g)
You would use Kilograms to weigh a cat.
gram
Milligram: to measure its mass.