Which law states that the pairs of homologous chromosomes separate so only one chromosome from each pair is present in each gamete?

• A. Law of Independent Assortment
• B. Law of Segregation of Alleles
• C. Law of Dominance
• D. Law of Crossing Over

Answer: (B)

During meiosis, homologous chromosomes pair and then separate so that each gamete gets only one chromosome from each pair. This reduction from diploid to haploid is the physical basis for Mendel's first law, often described at the allele level as the law of segregation of alleles: alleles for a gene separate into different gametes, so a gamete carries one copy of each gene. The description in the question matches this separation of chromosome pairs, which is why this choice is the best fit. Other options refer to different processes—independent assortment, which involves how different chromosome pairs align and segregate; crossing over, which is recombination between homologous chromosomes; and dominance, which concerns how alleles are expressed—none of these describes the actual separation of homologous chromosomes into gametes.