Answer: The correct answer is 'a balance'.
Explanation:
Mass: It is a measure of quantity of matter contained by an object. It is measured y the help of a balance which compares the mass of an unknown object with the known mass
Tool used to measure the mass of the package which is being mailed is a balance.
where as ruler is used to measure the length.
Marked beaker and graduated cylinder is used to measure volume of the liquids.
Hence, the correct answer is'a balance'.
