Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
Meiotic division is a reductional division. It occurs in reproductive cells as it helps to maintain the fixed number of chromosomes in sexually reproducing organisms. Prophase-I of meiotic division is a long phase, which is divided into five subphases, i.e. leptotene, zygotene, pachytene, diplotene and diakinesis. Synapsis or Pairing of chromosomes occurs during the zygotene stage.