A milliNewton.
the metric unit of force and weight is a: newton
The basic metric unit for weight is the newton.
Weight is force. The metric unit of force is the Newton.
Because a pencil has a mass of a few grams.
Centimetre
An appropriate metric unit of mass for a pencil would be grams.
What is the metric unit of a orange? What is the metric unit of a pencil? What iw the customary unit amount of water a bathtub will hold?
the metric unit of force and weight is a: newton
The basic metric unit for weight is the newton.
Weight is force. The metric unit of force is the Newton.
centimeter
Because a pencil has a mass of a few grams.
Any metric unit would do. But it might be easier to pick something smaller than the length of the pencil, like a centimeter, or a millimeter.
Nothing can 'weigh' two grams, because the gram is not a unit of weight (it is the metric unit of mass). However, two grams would likely weigh something close to the weight of a pencil.
The metric unit for an elephant's weight is typically measured in kilograms (kg).
Centimetre
You can use millimeters.