sentence2_structure: dna replication<>occurs<>in the cell cycle<>During the synthesis phase
sentence1: 5.3.1.5 Inhibition of DNA synthesis in Chinese hamster ovary (CHO) cells Powdered nickel blocked progression through S phase of the cell cycle (DNA replication) in cultured CHO cells in a flow cytometric assay (Costa et al.
sentence2: During the synthesis phase, dna replication occurs in the cell cycle.
question: What phase does dna replication occur in the cell cycle?