[" 4.Match the following column-A with "],[" column-B "],[[" Column-A "],[" (phases) "],[" Column-B "],[" (Their events) "]],[" a.Leptotene "," 1.Crossing over "],[" b.Zygotene "," 2.Desynapsis "],[" c.Pachytene "," 3.Synapsis "],[" d.Diplotene "," 4.Bouquet stage "]