The amount of gravity by an object is proportional to the mass of the object. In other words, objects with more mass will exert more gravity than objects with less mass. Distance also affects gravity. The amount of gravity decreases as the distance between two objects increases. These changes in the amount of gravity occur even on Earth. The farther away you are from the center of the Earth, the less gravity there is between you and the Earth. If you were on the Moon, the amount of gravity between you and the Earth would be even less.
Which word would best replace the underlined word to make the meaning more precise?