Answer:
Spring
Explanation:
Gravitational pull is affected by mass and distance. Since the moon’s mass does not change, the moon’s distance between Earth and the moon is the main consideration for the strength of lunar gravity. The moon’s pull on Earth waxes and wanes as the moon follows its elliptical orbit around the Earth, the distance between the two celestial objects increases and decreases. When they are nearest to each other, the moon is in the point of its orbit called the perigee, and its pull on Earth is the strongest.
On Earth, the moon’s gravity primarily is manifested as high and low tides, as the water bulges toward the moon. The effects of lunar gravity are felt the most at the constantly changing spot on Earth that is directly beneath the moon, called the sub-lunar point. At most times of the year, the moon has a greater pull on Earth than the sun does, but this changes during the times of year when the Earth’s orbit brings it closer to the sun. At these times, the sun’s gravitational pull causes spring tides, and when these coincide with the moon’s orbital perigee around the Earth, they are called perigean spring tides.
Earth exerts a gravitational pull on the moon 80 times stronger than the moon’s pull on the Earth. Over a very long time, the moon’s rotations created fiction with the Earth’s tugging back, until the moon’s orbit and rotational locked with Earth. This is called "tidal locking," and it explains why the same side of the moon always faces the Earth.
