the S phase (Synthesis phase) is the specific period during the cell cycle when DNA synthesis or replication takes place . During this time, the amount of DNA per cell doubles (e.g., from 2C to 4C), although the chromosome number remains the same (2n) . In contrast, the G1 phase is for metabolic growth without replication, the G2 phase involves protein synthesis for mitosis, and the M phase is the actual site of cell division . Mastering these specific cell cycle events is a high-priority strategy, as NCERT textbooks serve as the primary source for approximately 95% of NEET Biology questions .