DNA replication is semi-conservative in that
DNA replication can only follow the replication fork on
the leading strand.
The two stands of the original
helix are conserved, but they become part of separate progeny DNAs.
The base sequence of a DNA a molecule is conserved, with
very high fidelity, in DNA replication.
The two strands of the original helix are not conserved,
but the base sequence in the DNA is preserved.