Which type of replication allows part of the parent DNA strand to be included in each new helix?

Semi-conservative replication is a key concept in DNA replication that ensures each new double helix retains one strand from the original parent DNA molecule. During this process, the two strands of the double helix are separated, and each serves as a template for the synthesis of a new complementary strand. As a result, each of the two resulting DNA molecules consists of one parent strand and one newly synthesized strand.

This mechanism is crucial for maintaining genetic fidelity, as it allows for accurate copying of the genetic information. By incorporating one original strand, the newly formed DNA helixes can preserve the sequence of nucleotides, while the new strand is synthesized based on the template of the parent strand.

In contrast, conservative replication would result in one molecule containing both original strands and another molecule with both new strands, which does not align with the actual biological process. Dispersive replication suggests that parental DNA is broken up and mixed with new DNA, which is not how DNA replication occurs. Continuous replication does not accurately describe the discrete nature of the replication process. Thus, semi-conservative replication is the correct mechanism that underlines how genetic information is accurately passed on during cell division.