Which is correct for meiotic metaphase-I ?

Options

A. Bivalents are arranged at equator.
B. Univalents are arranged at equator.
C. Non-homologous chromosomes form pair.
D. Spindle fibres are attached at chromomere.

Answer

**Step-by-Step Solution:**

1. **Understanding Meiosis**: Meiosis is a type of cell division that reduces the chromosome number by half and is essential for sexual reproduction. It consists of two main stages: Meiosis I and Meiosis II. Each of these stages has several phases, including prophase, metaphase, anaphase, and telophase.

2. **Focus on Metaphase I**: In Meiosis I, Metaphase I is a crucial phase where homologous chromosomes (bivalents) align at the metaphase plate. This is different from Metaphase II, where individual chromosomes (univalents) align.

3. **Arrangement of Chromosomes**: During Metaphase I, homologous chromosomes (bivalents) are arranged at the equatorial plane of the cell. This arrangement is essential for the proper segregation of chromosomes during the next phase (Anaphase I).

4. **Kinetochore Microtubules**: The spindle fibers (kinetochore microtubules) attach to the kinetochores of each homologous chromosome. This attachment is crucial for the movement of chromosomes during cell division.

5. **Independent Assortment**: The orientation of each bivalent at the metaphase plate is random, which contributes to genetic diversity through independent assortment. This means that the way one pair of homologous chromosomes aligns does not affect how another pair aligns.

6. **Conclusion**: Based on the above understanding, the correct statement regarding meiotic metaphase I is that "bivalents are arranged at the equator."

**Final Answer**: The correct option for meiotic metaphase I is that **bivalents are arranged at the equator**.

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