The surface of the Earth shows fewer meteor impact craters when compared to the surface of Mercury or our own Moon, which show thousands of impact craters each? Think of four specific reasons to explain this

Here are 4 reasons I came up with.

1. Water

Earth is the only planet that has water on its surface. Water is a major cause of surface erosion.

Surface water may hide crater like features. One of Jupiter's moons (Europa) is covered with ice, and it is the smoothest object in the solar system. Meteors impacts just create a big "splash" and the surface rearranges itself quite rapidly.

2. Atmosphere.

Atmospheric winds are also one of the players in surface erosion. The Moon and Mercury do not have any atmosphere, so surface features are not disturbed by wind (see for example the astronaut's foot prints on the moon).

3. Atmosphere.

In the lower layers of the atmosphere the wind play a major role in surface erosion and erase any impact crater.
However to create a crater the object must hit earth first. The friction force the atmosphere exerts on any high-speed flying objects creates huge amount of heat that usually van evaporate small objects completely or reduce the size of a potential meteor quite dramatically. By the time this object reaches the earth's surface, the impact energy is not as large.

4. Molten core

Unlike the moon and mercury, Earth has a molten iron core. This causes the surface of the earth to rearrange itself constantly (earthquakes, volcanoes). These dynamic properties of the surface can, over long period of time, erase any impact features.