Assertion : Primary growth of the plants contributes to the elongation of the plants along their axis.
Reason : Root apical meristem and shoot apical meristem are responsible for primary growth of the plants.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false

Explanation

To solve the question regarding the assertion and reason statements about plant growth, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Assertion**: The assertion states that "Primary growth of the plants contributes to the elongation of the plants along their axis." This means that primary growth is responsible for making plants taller or longer.

2. **Understand the Reason**: The reason given is that "Root apical meristem and shoot apical meristem are responsible for primary growth of the plants." This indicates that the specific regions of the plant (the root and shoot apical meristems) are the areas where primary growth occurs.

3. **Evaluate the Truth of the Assertion**:
- Primary growth indeed contributes to the elongation of plants. This is a well-established fact in plant biology, as primary growth occurs at the tips of roots and shoots, allowing them to grow longer.

4. **Evaluate the Truth of the Reason**:
- The root apical meristem and shoot apical meristem are indeed responsible for primary growth. These meristems are regions of actively dividing cells that lead to the increase in length of the plant.

5. **Determine the Relationship**:
- Since both the assertion and the reason are true, we need to check if the reason correctly explains the assertion. The reason explains that the apical meristems are the sites of primary growth, which directly leads to the elongation mentioned in the assertion.

6. **Conclusion**:
- Both the assertion and reason are true, and the reason provides a correct explanation for the assertion. Therefore, the answer is that both statements are true, and the reason is the correct explanation of the assertion.

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

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