Final answer:
The double-stranded breaks in meiosis begin in the leptotene stage and recombination is complete by late pachytene.
Step-by-step explanation:
The question concerns the specific stages of meiosis when double-stranded DNA breaks begin and when recombination is completed. Double-stranded breaks start in the leptotene stage of prophase I and recombination is completed by the end of the pachytene stage. Therefore, the correct answer to the student's question is "Double-stranded breaks begin in leptotene, and recombination is complete by late pachytene." This is supported by the process described where during prophase I, the synaptonemal complex forms, and homologous chromosomes undergo crossing over at the points marked by recombination nodules. When the synaptonemal complex breaks down by the end of the pachytene stage, the chromosomes have already exchanged DNA and form chiasmata, holding the homologs together until they are separated during anaphase I.