During meiosis I, crossing over occurs to

• A. Aligns chromosomes at the metaphase plate.
• B. Replicates DNA prior to meiosis.
• C. Exchanges DNA between homologous chromosomes, creating new allele combinations.
• D. Produces identical chromatids.

Answer: (C)

Crossing over during meiosis I reshuffles genetic material by exchanging segments between homologous chromosomes, specifically between non-sister chromatids. This creates recombinant chromatids with new allele combinations, increasing genetic diversity in gametes. It happens in prophase I when homologues pair up, not during metaphase alignment or DNA replication, and it results in chromatids that are not identical rather than identical copies.