What does it mean when DNA replication is described as semi-conservative?

Describing DNA replication as semi-conservative means that each of the two new double helices formed during replication contains one original strand from the parental DNA and one newly synthesized strand. This process allows for the retention of half of the original molecule, ensuring that genetic information is preserved in the new DNA strands.

During the replication process, the double helix unwinds, and each original strand serves as a template for the formation of a new complementary strand. As a result, each daughter DNA molecule retains a single strand from the parent, making the replication process "semi-conservative."

The other options do not accurately describe the semi-conservative nature of DNA replication. For instance, claiming that both strands are newly synthesized neglects the important aspect of conserving the original strands. Regarding energy conservation, while replication does require energy, this is not the defining characteristic of being semi-conservative. Lastly, replication stages are a separate consideration that does not inherently relate to the concept of semi-conservativeness.