It is called Mass.
Among the physical characteristics of a matter which includes Weight, Mass, Volume, and Density the only characteristic that does not change is the mass. The mass of an object never change from place to place. All the objects have a mass and that is why there is a weight but it changes depends on the gravity. Mass don't.
Using coupons seems like an old-fashioned, time-consuming way to save a few cents on the products you buy at the grocery store. After all, most coupons don't usually have a face value of more than $1 and, quite often, they're worth far less. But done properly, couponing can save you thousands of dollars every year.
Answer:
i think it's C
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