Answer:
D
Step-by-step explanation:
Key points:
- Cells have a variety of mechanisms to prevent mutations, or permanent changes in DNA sequence.
- During DNA synthesis, most DNA polymerases "check their work," fixing the majority of mispaired bases in a process called proofreading.
- Immediately after DNA synthesis, any remaining mispaired bases can be detected and replaced in a process called mismatch repair.
- If DNA gets damaged, it can be repaired by various mechanisms, including chemical reversal, excision repair, and double-stranded break repair.
that's from khan academy^