Question

Dna repair system operated when enviromental agent damage dna

Answer 1

Explanation:

End-Joining Repair of Nonhomologous DNA Double-strand breaks are caused by ionizing radiation and by anticancer drugs, such as bleomycin, which is why these drugs are used to kill rapidly growing cells. ... Formation of such a possibly mutagenic deletion is one example of how repair of DNA damage can introduce mutations.

Answer 2

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At least five major DNA repair pathways—base excision repair (BER), nucleotide excision repair (NER), mismatch repair (MMR), homologous recombination (HR) and non-homologous end joining (NHEJ)—are active throughout different stages of the cell cycle, allowing the cells to repair the DNA damage.