grams (for their mass), centimetres (for length), millimetres (for thickness/height), possibly Mohs scale for hardness.
Centimeters
Pencil lead is very narrow. Millimeter can be used to measure it.
you would use gallons
The answer will depend on whether you want the mass of a pencil, its weight, its length, width, volume. You may want to measure its colour!
The best unit for measuring the length of a pencil is inches.
You would measure it in centimeters.
most likely in grams
Centimeters
Centimeters
Centimeters
Millimetres, centimetres or inches
Millimeters.
Pencil lead is very narrow. Millimeter can be used to measure it.
Inches (or centimeters, if you're working in the metric system).
millimetres
The ounce.
centimeter