Answer: At which stage are the replicated chromosomes condensed, homologous chromosomes form bivalents, and crossing over occurs The correct answer is 1) Prophase I of meiosis.
Step-by-step explanation:
1. Condensation of replicated chromosomes: The replicated chromosomes condense, becoming shorter and thicker. This condensation allows for easier manipulation and movement of the chromosomes during subsequent stages of meiosis.
2. Homologous chromosomes form bivalents: Homologous chromosomes, which are pairs of chromosomes that contain similar genetic information, come together and align side by side. This alignment forms structures called bivalents or tetrads.
3. Crossing over occurs: Crossing over is the exchange of genetic material between homologous chromosomes. During Prophase I, sections of DNA between non-sister chromatids of homologous chromosomes break and swap places. This genetic recombination increases genetic diversity in offspring.
Overall, Prophase I of meiosis is a crucial stage where replicated chromosomes condense, homologous chromosomes align, and crossing over occurs. These processes contribute to the genetic variation in gametes, which is essential for sexual reproduction and the production of genetically diverse offspring.