When paternal and maternal chromosomes change their materials with each other in cell division this event is called (a) bivalentforming (b) dyadforming (c) synapsis (d) crossingover.
Option D Crossing over is responsible for inducing variability. It involves an exchange of equal segments of nonsister chromatids belonging to two different but homologous chromosomes. Crossing over takes place at four stranded stage. Only two of the four chromatids take part in crossing over. The other two are called non crossovers. Zygotene is characterized by pairing of homologous chromosomes which is called synapsis. The first meiotic division which is completed at first telophase may be followed by cytokinesis giving rise to a dyad.
