What distinguishes mass from weight? a. mass is a measure of the amount of matter in an object, while weight is a measure of the force of gravity on the object. b. weight is a measure of the amount of matter in an object, while mass is a measure of the force of gravity on the object. c. mass is a measure of an object's inertial force, and weight is the force exerted by that object on other objects. d. mass and weight are synonyms and ultimately describe the same principle.

The correct answer is
A. Mass is a measure of the amount of matter in an object, while weight is a measure of the force of gravity on the object.

In fact, mass is an intrinsic property of any object: it does not depend on external conditions, and it gives a measure of the amount of matter in the object.
Weight, instead, is the measure of the force of gravity on the object. Weight is related to the mass by the equation:

where
W is the weight
m is the mass
g is the gravitational acceleration

From the formula, we see that the weight is proportional to the mass, but it also depends on strength of the gravitational field g, which is not constant (for instance, g is different if we are on another planet, or very far from Earth's surface).