What term refers to the amount of matter in a body?

The correct answer, mass, refers specifically to the amount of matter contained in an object or body. In physical science, mass is a scalar quantity measured in kilograms or grams and does not change regardless of the object's location.

Weight, on the other hand, is the force exerted by gravity on an object, which can vary based on the gravitational field strength of the planet where the object is located; hence it is not an accurate measure of the amount of matter. Volume refers to the amount of space an object occupies, typically measured in liters or cubic meters, rather than the amount of matter itself. Density is defined as mass per unit volume, providing a relationship between mass and volume but not measuring either quantity independently.

Thus, mass is the most appropriate term when discussing the total amount of matter in a body.