Q: Passage: Chromosomal crossover (or crossing over) is the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes during sexual reproduction. It is one of the final phases of genetic recombination, which occurs in the pachytene stage of prophase I of meiosis during a process called synapsis. Synapsis begins before the synaptonemal complex develops and is not completed until near the end of prophase I. Crossover usually occurs when matching regions on matching chromosomes break and then reconnect to the other chromosome.

Question: Based on this passage, when does the crossing over occur in meiosis? Let's give stream of consciousness first:
To answer the above question, the relevant sentence is: It is one of the final phases of genetic recombination, which occurs in the pachytene stage of prophase I of meiosis during a process called synapsis. Therefore, the final answer is in the pachytene stage of prophase I of meiosis during a process called synapsis.