Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The ploidy of a cell remains unchanged after passing through the S phase of the cell cycle. Reason (R): During the S phase, the centromeres split, causing the chromosome number to double along with the DNA content. In the light of the above statements, choose the most appropriate answer from the op

Step-by-step solution

Assertion (A) is true: The ploidy (chromosome number) of a cell does not change during the S phase. A diploid cell remains diploid. Reason (R) is false: During the S phase, the amount of DNA per cell doubles due to DNA replication. However, the centromeres do not split during this phase; the newly formed sister chromatids remain attached to the same centromere. Centromere splitting occurs later, during the anaphase of mitosis (or anaphase II of meiosis). Because the centromeres do not split in the S phase, the chro