Meiosis II fails after completion of meiosis I. The phenomenon is

Options

A. Brachymeiosis
B. Dinomitosis
C. Karyokinesis
D. None of the above

Answer

**Step-by-Step Solution:**

1. **Understanding Meiosis**: Meiosis is a type of cell division that reduces the chromosome number by half, resulting in four haploid cells from one diploid cell. It consists of two main stages: Meiosis I and Meiosis II.

2. **Completion of Meiosis I**: In this scenario, we are told that Meiosis I has been completed successfully. This means that the homologous chromosomes have been separated, and the cell is now ready to enter Meiosis II.

3. **Failure of Meiosis II**: The question states that Meiosis II fails after the completion of Meiosis I. This indicates that while the first meiotic division occurred properly, the second division does not take place.

4. **Identifying the Phenomenon**: The phenomenon where Meiosis II fails after Meiosis I is specifically known as **brachymeiosis**. This term is used to describe a situation where only Meiosis I occurs effectively, and Meiosis II does not proceed.

5. **Examples of Brachymeiosis**: Brachymeiosis is commonly observed in certain fungi during the formation of ascospores from the ascus (the mother ascus). This is an important point that highlights the biological relevance of this phenomenon.

6. **Eliminating Other Options**:
- **Dynamitosis**: This is a type of cell division found in dinoflagellates where the nuclear membrane persists during division, which is not applicable here.
- **Karyokinosis**: This term refers to the division of the nucleus and occurs in both mitosis and meiosis, but it does not specifically relate to the failure of Meiosis II.
- **None of the Above**: Since we have identified brachymeiosis as the correct term, this option is also incorrect.

7. **Conclusion**: Therefore, the correct answer to the question is **brachymeiosis**.