Final answer:
Synapsis during meiosis I is vital for pairing homologous chromosomes, allowing genetic recombination, and leading to the halving of chromosome number, essential for the production of haploid gametes.
Step-by-step explanation:
Synapsis is a crucial step in meiosis I where homologous chromosomes pair tightly together through a complex known as the synaptonemal complex. This pairing is essential for the process of reduction division, which reduces the chromosome number by half. During prophase I, synapsis ensures the precise alignment of genes between the chromatids, enabling crossover or genetic recombination to occur at points called chiasmata.
This exchange of genetic material contributes to genetic diversity. As meiosis I progresses, the breakdown of the synaptonemal complex and subsequent separation of homologous chromosomes at anaphase I leads to the reduction of the ploidy level from diploid to haploid, ensuring each daughter cell receives one set of chromosomes.