A : Each chromosome of bivalent attaches with two spindles in metaphase. Reason : in metaphase bivalents migrate towards metaphasic plate

Options

A. IF both Assertion & Reason are true and the reason followed is the correct explanation of the assertion then mark (1).
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion then mark (2).
C. If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statement then mark (4).

Answer

To solve the assertion and reason question regarding bivalent chromosomes during metaphase, we will analyze both statements step by step.

### Step-by-Step Solution:

1. **Understanding Bivalent Chromosomes**:
- Bivalent chromosomes consist of two homologous chromosomes that have paired together during meiosis. Each homologous chromosome is made up of two sister chromatids, resulting in a total of four chromatids in a bivalent, also referred to as a tetrad.

**Hint**: Remember that "bivalent" means two homologous chromosomes paired together.

2. **Assertion Analysis**:
- The assertion states, "Each chromosome of bivalent attaches with two spindles in metaphase."
- In metaphase, each chromosome of the bivalent actually attaches to one spindle fiber from each pole of the cell. Therefore, each homologous chromosome in the bivalent attaches to a single spindle fiber, not two.

**Hint**: Think about how spindle fibers connect to chromosomes during cell division.

3. **Reason Analysis**:
- The reason states, "In metaphase, bivalents migrate towards the metaphase plate."
- This statement is true. During metaphase I of meiosis, bivalents align themselves along the metaphase plate and are pulled by spindle fibers towards the center of the cell.

**Hint**: Consider the role of spindle fibers in aligning chromosomes during metaphase.

4. **Conclusion**:
- Since the assertion is false (each chromosome of the bivalent does not attach to two spindles) and the reason is true (bivalents do migrate towards the metaphase plate), the correct answer is that the assertion is false, and the reason is true.

**Hint**: When evaluating assertion-reason questions, determine the truth value of each statement independently.

### Final Answer:
- The assertion is false, and the reason is true. Therefore, the correct option is that the assertion is false and the reason is true.