A : Most of the species of Chara are monoecious but show cross fertilization
R : The plant body shows protandrous condition .

Options

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

Answer

### Step-by-Step Solution:

1. **Understanding the Terms:**
- **Monoecious:** This term refers to organisms that have both male and female reproductive organs in the same individual. In this case, Chara has both male (antheridia) and female (oogonia) structures in the same plant body.
- **Cross Fertilization:** This is a reproductive process where male and female gametes come from different individuals, leading to genetic diversity.

2. **Analyzing the Assertion:**
- The assertion states that "Most of the species of Chara are monoecious but show cross fertilization."
- This is true because, despite having both reproductive organs, Chara often relies on gametes from different individuals for fertilization, which is a strategy to enhance genetic variation.

3. **Understanding the Reason:**
- The reason provided is that "The plant body shows protandrous condition."
- Protandry is a condition where the male reproductive organs mature before the female reproductive organs. In Chara, this means that the antheridia (male organs) mature first, allowing them to release sperm before the oogonia (female organs) are ready to receive them.

4. **Connecting Assertion and Reason:**
- Since Chara is monoecious but has a protandrous condition, the male gametes are released before the female gametes are mature. This leads to cross fertilization as the male gametes must find and fertilize the eggs from other individuals, as the female gametes are not ready in the same plant.

5. **Conclusion:**
- Both the assertion and the reason are true. The reason correctly explains why the assertion is true. Therefore, the correct answer is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.

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

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