The “S” phase which is the phase of DNA synthesis
<span> Endoplasmic Reticula should be the answer but if it is not my apologies </span>
Answer:

point mutation, change within a gene in which one base pair in the DNA sequence is altered. Point mutations are frequently the result of mistakes made during DNA replication, although modification of DNA, such as through exposure to X-rays or to ultraviolet radiation, also can induce point mutations
The S interphase is when the DNA splits into two copies of itself