Explanation

Synapsis is the pairing of homologous chromosomes during the zygotene stage of meiosis. Each pair is called bivalent. One chromosome of the pair comes from the male parent and other from the female parent. Each member of the pair is of the same length, their centromeres are in the same position and they usually have the same number of genes arranged in the same order. After zygotene stage, cell entered in pachytene stage in which the bivalents become spiralled, shortened and thickened.