Which process directly contributes to genetic variation during sexual reproduction?

• A. Mitosis
• B. DNA replication
• C. Crossing over during meiosis
• D. Binary fission

Answer: (C)

Genetic variation in offspring comes from reshuffling genetic material when gametes are formed. Crossing over during meiosis is the process where homologous chromosomes pair up and exchange segments, creating chromosomes with new combinations of alleles. This shuffling produces gametes that carry unique allele patterns, increasing diversity in the next generation. Other options don’t introduce these new allele combinations: mitosis yields two identical cells, DNA replication just duplicates the genome without creating new combinations, and binary fission is an asexual process that does not mix genetic material from two parents. So crossing over during meiosis directly contributes to genetic variation in sexual reproduction.