Homologous recombination is an important mechanism in which organisms use a "backup" copy of the DNA as a template to fix double-strand breaks without loss of genetic information. Which of the following is not necessary for homologous recombination to occur?
(a) 3' DNA strand overhangs
(b) 5' DNA strand overhangs
(c) a long stretch of sequence similarity
(d) nucleases
Answer: B