Answer:
18 grams
Step-by-step explanation:
The mass of an object is the object's fundamental property. It is the amount or quantity of mater in the object. Irrespective of the object's location or the gravitational force applied on the object, the mass of an object remains the same. In other words, the mass of an object is the same everywhere.
The mass should however not be confused with its weight which depends on the mass and the gravitational force applied on it.
In summary, whether on earth or in the moon, the mass of an object remains the same. If the mass of the object is 18 grams on earth, it will also be 18 grams in the moon.