The major way that meiosis II differs from mitosis is that:

• A. DNA replication occurs before both meiosis II and mitosis
• B. sister chromatids do not separate during meiosis II
• C. the cells entering meiosis II are haploid, while those entering mitosis are diploid
• D. crossing over occurs during meiosis II but not during mitosis

Answer: (C)

Verified step by step guidance

1. Understand the key difference between meiosis II and mitosis: Meiosis II occurs after meiosis I, where homologous chromosomes separate, resulting in haploid cells. Mitosis, on the other hand, starts with diploid cells and maintains the diploid state throughout.
2. Recall that DNA replication does not occur before meiosis II. DNA replication occurs only once, during the S phase of interphase, prior to meiosis I or mitosis.
3. Recognize that sister chromatids do separate during meiosis II, similar to what happens in mitosis. This is a shared feature between the two processes.
4. Note that crossing over occurs during meiosis I, not meiosis II. Crossing over is a process where homologous chromosomes exchange genetic material, increasing genetic diversity. This does not happen in mitosis.
5. Conclude that the major difference is the ploidy of the cells entering the process: cells entering meiosis II are haploid (n), while cells entering mitosis are diploid (2n). This distinction is critical to understanding the unique roles of meiosis and mitosis in cell division.