What is a characteristic of the elongation phase during DNA replication?

The elongation phase during DNA replication is characterized by the synthesis of new DNA strands, which occurs continuously on one strand (the leading strand) and discontinuously on the other strand (the lagging strand). This discontinuous replication on the lagging strand leads to the formation of short segments known as Okazaki fragments. These fragments are synthesized separately and later joined together.

This characteristic of synthesizing DNA segments is crucial because it ensures that both strands of the double helix are replicated accurately and efficiently. The other choices, such as the separation of DNA strands, describe an earlier phase of replication; the synthesis of only one strand is incorrect because both strands are synthesized, albeit in different manners; and while DNA ligase is indeed involved in joining the fragments, it is not the primary activity occurring during the elongation phase itself. Therefore, the synthesis occurring in segments is the defining characteristic of this phase.