Which method (s) can be used to join double-stranded breaks in DNA? (choose all that apply)

a. homologous end joining

b. polymerase chain reaction

c. homologous recombination

d. Non-homologous end joining

Option (a) and (d).

Explanation:

The breaks in DNA molecule may occur due to replication error and oxidizing agent. The double-stranded breaks in DNA can be corrected by Homologous end joining and non homologous end joining.

Homologous end joining is used to repair the DNA present in G2 nad S phases of the cell cycle. The homologous sequences of DNA is used to repair the DNA. Non homologous end joining occurs in the cell present at G0 and G1 phase of the cell cycle. The DNA broken ends are juxtaposed and later rejoin together by DNA ligase.

Thus, the correct answer is option (a) and (d).