Grams
I will measure a book with grams
The mass or weight or a ruler would best be measured in grams.
Kilogram
three grams
A gram, as there are 1000 grams in a kilogram. A penny only weighs a few grams anyway.
Kilograms
Grams
A kilogram.
it would be a gram and if you didn't know a kilogram is equal to 1,000 grams
in grams
Strawberries would be measured in grams or ounces.
Kilogram is a measure of weight - so you would use it to weight something. You would probably use it for objects that are large enough to make using grams unnecessary.