Select all the events that occur during prophase I

Select all the events that occur during prophase I. 

The correct answer and explanation is:

iturn0image0Prophase I is a pivotal stage in meiosis, characterized by several key events that ensure accurate segregation of genetic material and contribute to genetic diversity. This phase is subdivided into five distinct substages: leptotene, zygotene, pachytene, diplotene, and diakinesis.

1. Leptotene: Chromosomes begin to condense, becoming visible as thin threads. Each chromosome consists of two sister chromatids, though they are not yet distinctly separate. citeturn0search14
2. Zygotene: Homologous chromosomes start pairing in a process called synapsis, facilitated by the formation of the synaptonemal complex. This pairing is crucial for subsequent genetic recombination. citeturn0search14
3. Pachytene: Synapsis completes, and crossing over occurs between non-sister chromatids of homologous chromosomes. This exchange of genetic material introduces genetic variation. citeturn0search14
4. Diplotene: The synaptonemal complex dissolves, and homologous chromosomes begin to separate but remain connected at chiasmata—the sites of crossing over. citeturn0search14
5. Diakinesis: Chromosomes condense further, chiasmata move toward chromosome ends (terminalization), the nucleolus disappears, and the nuclear envelope disintegrates, marking the end of prophase I. citeturn0search14

Collectively, these events during prophase I are essential for the accurate segregation of homologous chromosomes and the generation of genetic diversity, which are fundamental to the process of sexual reproduction.