Centimetres, millimetres or inches would be most appropriate for measuring the length of a ruler.
Micrometer
Centimeters
Centimeters
To measure the mass of a pencil, you would typically use a scale or a balance. Place the pencil on the scale or balance, and the device will provide you with the measurement of the pencil's mass in grams or ounces.
The length of a pencil. your waist/chest measurement the dimensions of a table
To measure the width of a pencil sharpener, you would typically use centimeters or millimeters, as these units provide a precise measurement suitable for small objects. For most pencil sharpeners, centimeters are convenient for general use, while millimeters can offer a more detailed measurement if needed.
You could measure the mass with grams.
To measure the thickness of a pencil lead, you can use a micrometer or caliper tool, which can provide a precise measurement in millimeters. Simply place the pencil lead between the jaws of the tool and gently close it to obtain the measurement.
No, a pencil is not a unit of measurement.
Millimeters
A vernier caliper would be a good way, unless you need a more accurate measurement, in which case I might use a micrometer caliper.
a ruler