Synapsis takes place in which sub-stage of meiosis I?

Explanation

Leptotene: This is the first sub-stage of meiosis. During leptotene, chromosomes condense and become visible as long, thread-like structures. Synapsis hasn't started yet in this stage.Zygotene: In the zygotene stage, homologous chromosomes start to pair up. This process is known as synapsis. The paired chromosomes are called tetrads and consist of one maternal and one paternal chromosome. This pairing is essential for recombination and genetic diversity.Pachytene: During pachytene, the homologous chromosomes are fully paired and aligned. This is when genetic recombination or crossing over occurs, where sections of chromatids are exchanged between homologous chromosomes. This further contributes to genetic diversity.Diplotene: In diplotene, the homologous chromosomes start to separate but remain attached at points called chiasmata, which are the sites where crossing over occurred. This stage marks the beginning of chromosome disjunction.Diakinesis is the final sub-stage of meiosis, and it involves the completion of chromosome condensation and the separation of homologous chromosomes. In this stage, chiasmata resolve, and the tetrads are held together only at the centromeres. This prepares the chromosomes for their eventual segregation during meiosis.These sub-stages of meiosis are essential for ensuring the proper reduction in chromosome number and genetic diversity in the resulting gametes.So the correct option is zygotene.