Multiple choice Crossing over takes place at a stage between leptotene and diplotene pachytene and diplotene zygotene and diplotene zygotene and pachytene Reveal answer Fill a bubble to check yourself C Correct answer Explanation Crossing over takes place at a stage between zygotene and diplotene. Crossing over is the exchange of genes between two chromosomes, resulting in non-identical chromatids that comprise the genetic material of gametes (sperm and eggs).