We know that every object exerts an attraction on every other object and the heavier the object the attraction.
i think the blank is "heavier," but i'm not completely sure.

I don't know what the exact word is, but I do know that the bigger an objects mass is the more it will attract other objects toward it, mainly smaller objects with less mass. it might be gravity or something around those linesis it a multiple choice question? 

Efficiency is an action of doing something. for example when you take a test. good efficiency means you did well but bad effeciency or no effiency means you did bad.

The correct answer is c. hope this