Gram
Milligrams.
The best unit is a litre.
The best unit for measuring the length of a pencil is inches.
inch
A millimetre.
centimetres
pounds
kilograms
For a desk like one used in schools the best unit would be pounds. Good luck on your measuring!
The best unit of measure to use when measuring the amount of water in a drinking glass is ounces. A liquid measuring cup can be used to measure the ounces of water.
The newton. (The kilogram is not a unit of weight or force.)
The appropriate unit for weight is a Newton.