Final answer:
DNA replication in vivo is described as 3) semi-discontinuous and semiconservative, where each new DNA molecule contains one original and one new strand, with the lagging strand synthesized in short segments later joined together.
Step-by-step explanation:
The term that accurately describes the replication of DNA in vivo is semidiscontinuous. DNA replication is semiconservative, which means that each new DNA molecule consists of one original strand and one newly synthesized strand. This was demonstrated by the famous Meselson and Stahl experiment. The replication process is also bidirectional, with both strands being replicated at the same time, but it is discontinuous on the lagging strand, where the new DNA is synthesized in short fragments called Okazaki fragments before being joined together.