Any eating utensil that you can find
The abundance of abiotic factors, like light, water, and shelter, limit the amount of biotic factors.
it's very practical, because it's on base 10, so conversion between stuff like meters to kilometer is always just a multiplication with 10 to some power
like 1 km = 1000m (10³m)
or 1 m = 10^-3km = 0.001km
same reason for other SI units.
except time, that's base 60, or 12, or 24. that's more complicated, but there isn't any real competition
