Question Detail
Question
Which of the following occurs during mitosis but not during meiosis I? a. Crossing over b. Reduction to diploid number of chromosomes to haploid c. The nuclear envelopes breaks down d. Separation of sister chromatids
Correct Answer
Option D is the correct answer.
Detailed Explanation
Sister chromatids separate during anaphase of mitosis and during anaphase II of meiosis, but they do NOT separate during meiosis I (homologous chromosomes separate in anaphase I). Nuclear envelope breakdown occurs in both. Crossing over and reduction to haploid are specific to meiosis I.
Hint
In meiosis I, it's the pairs of chromosomes that separate, not the copies of each chromosome.