Answer: The distance between the objects.
Explanation: The equation for the gravitational force is written as:
F = G*m1*m2/r^2
Where r is the distance between the objects, m1 and m2 are the masses and G is the gravitational constant.
This cuantity is in the denominator because, as larger is the distance, smaller is the strenght of the field.
And is squared because is a force that spreads in a solid angle (as the change of area in a growing sphere )
