These morphological differences are thought to reflect compositional differences (i.e., interlayered ice, rock, or water) in the subsurface at the time of impact.
In reality, gravitational acceleration (symbol: "g") varies slightly with latitude, elevation and subsurface density; these variations are typically only a few tenths of a percent.
It is the deepest-living animal ever found, able to withstand heat and crushing pressure, and the first multicellular organism found at deep subsurface levels.