Answer:
the most important effect of the gravitational force is the change in the tide.
Step-by-step explanation:
The gravitational force between the Moon and the Earth is given by
F = G m M / r2
where m is the mass of the Moon, M the mass of the Earth, and r the distance between the two.
The magnitude that changes in this formula is the distance between the Moon and the Earth, due to the lunar rotation, at the points of maximum approach in the periods of high tide and in the periods of greater distance the tide is low.
It should be mentioned that the earth's crust is also affected, but its movement is much less than that of water, which is why in almost all cases it is taken as fixed.
Lately it has also been analyzed that the Earth-Moon structure creates greater stability in the rotation of the two bodies.
Consequently the most important effect of the gravitational force is the change in the tide.