What property measures the quantity of matter in an object?

Mass is defined as the measure of the amount of matter in an object. It is a fundamental property that does not change regardless of the object's location, whether it is on Earth, the Moon, or in outer space. This stability distinguishes mass from weight, which is the force exerted by gravity on that mass and can vary depending on the gravitational field strength.

Density measures how much mass is contained in a given volume, and volume refers to the amount of space an object occupies. While both density and volume are important physical properties, they do not independently signify the total quantity of matter. Therefore, mass is the most direct representation of the matter within an object, making it the correct answer. Understanding mass is essential in fields such as physics and engineering, where calculations involving forces, materials, and structures rely on accurate measurements of mass.