A : Anaphase-I is actual phase of reduction in number of chromosomes.
R : Homologous chromosomes move to the opposite poles with both their chromatids.

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-reason question regarding Anaphase I of meiosis, we will analyze both the assertion (A) and the reason (R) step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Anaphase I is the actual phase of reduction in the number of chromosomes."
- During Anaphase I of meiosis, homologous chromosomes are separated and pulled towards opposite poles of the cell. This separation leads to a reduction in chromosome number because each daughter cell will receive only one chromosome from each homologous pair.

2. **Understanding the Reason (R)**:
- The reason states that "Homologous chromosomes move to the opposite poles with both their chromatids."
- In Anaphase I, it is indeed true that homologous chromosomes (each consisting of two sister chromatids) move towards opposite poles. This movement is crucial for ensuring that each daughter cell receives only one chromosome from each pair.

3. **Evaluating the Truth of A and R**:
- Both the assertion and the reason are true statements. Anaphase I is indeed the phase where the reduction in chromosome number occurs, and the movement of homologous chromosomes to opposite poles is a key feature of this phase.

4. **Determining the Relationship Between A and R**:
- The reason (R) provides a correct explanation for the assertion (A). The movement of homologous chromosomes to opposite poles during Anaphase I directly results in the reduction of chromosome number, which is what the assertion claims.

5. **Conclusion**:
- Since both the assertion and the reason are true, and the reason correctly explains the assertion, the correct answer is that both A and R are true, and R is the correct explanation of A.

### Final Answer:
Both assertion and reason are true, and the reason is the correct explanation of the assertion.

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