Complex sentence: The unit used in the object diameter will result in the smallest resolvable features at that unit, in the above example they are approximated in kilometers resulting in the smallest resolvable Moon craters being 3.22 km in diameter.
Split into simpler sentences: The unit used in the object diameter results in the smallest resolvable features at that unit. In the above example they are approximated in kilometers resulting in the smallest resolvable Moon craters being 3.22 km in diameter.