earth's surface is considered "young" because there are very few visible impact craters. describe at least three causes/processes responsible for earth having so few impact craters relative to the "older" surface of the moon, despite throughout geological history having been impacted at the same rate.

Earth has so few impact craters compared to the Moon because of erosion, plate tectonics, and volcanoes.

1. Erosion

Weather, running water, and plants all wear down the ground and level it out. The moon has none of these.

2. Plate tectonics

The Earths surface consists of several tectonic plates floating over a liquid core.

As the plates tear apart and crush against each other, new rocks form and older ones disappear.

Over billions of years, all traces of old impact craters have disappeared.

The moon has no moving plates, so tectonics cannot remove lunar craters.  

3. Volcanoes

Volcanic flows cover up impact craters. The Moon has not had active volcanoes for three billion years.

a and b because with the other three, they simplify to something else.