An important result of meiosis is that:

• A. genetically identical cells are produced
• B. the chromosome number is reduced by half in gametes
• C. sister chromatids remain attached in all daughter cells
• D. DNA replication occurs twice

Answer: (B)

Verified step by step guidance

1. Understand the purpose of meiosis: Meiosis is a type of cell division that reduces the chromosome number by half, producing four haploid gametes (sperm or egg cells) from a diploid parent cell. This is essential for sexual reproduction to maintain the species' chromosome number across generations.
2. Review the key events in meiosis: Meiosis consists of two stages, Meiosis I and Meiosis II. In Meiosis I, homologous chromosomes are separated, reducing the chromosome number by half. In Meiosis II, sister chromatids are separated, similar to mitosis.
3. Analyze the options: The first option, 'genetically identical cells are produced,' is incorrect because meiosis results in genetically diverse cells due to crossing over and independent assortment. The second option, 'the chromosome number is reduced by half in gametes,' aligns with the purpose of meiosis. The third option, 'sister chromatids remain attached in all daughter cells,' is incorrect because sister chromatids are separated during Meiosis II. The fourth option, 'DNA replication occurs twice,' is incorrect because DNA replication occurs only once, during the S phase of interphase, before meiosis begins.
4. Focus on the correct answer: The chromosome number is reduced by half in gametes. This reduction ensures that when two gametes fuse during fertilization, the resulting zygote has the correct diploid chromosome number.
5. Summarize the importance: Meiosis not only reduces the chromosome number by half but also introduces genetic variation through processes like crossing over (exchange of genetic material between homologous chromosomes) and independent assortment (random distribution of homologous chromosomes).