○○○ erosion ⪢⪢
The reason we don't see the asteroid impacts on earth the same way we see the craters on the moon is because on earth those craters have been wiped away by the action of
weather and erosion and
weathering and the movement of tectonic plates.
http://qindex.info/i.php?x=10140
• weather instruments
○○○ element ⪢⪢
