Assertion (A): Calcium is required by meristematic and differentiating tissues.
Reason (R): Calcium participates in middle lamella synthesis.

Options

A. Both (A) and (R) are true and (R) is the correct explanation of A.
B. Both (A) and (R) are true and (R) is not the correct explanation of A.
C. (A) is a true statement but (R) is false.
D. Both (A) and (R) are false.

Answer

To analyze the assertion and reason provided in the question, we can break it down into steps:

### Step 1: Understand the Assertion (A)
The assertion states that "Calcium is required by meristematic and differentiating tissues."
- **Explanation**: Meristematic tissues are regions of actively dividing cells in plants, found in areas like the tips of roots and shoots. These tissues are crucial for plant growth and development. Calcium is an essential nutrient that plays a significant role in cell division and growth.

### Step 2: Understand the Reason (R)
The reason states that "Calcium participates in middle lamella synthesis."
- **Explanation**: The middle lamella is a layer that cements together the cell walls of adjacent plant cells. It is primarily composed of pectins, and calcium ions help in the formation and stabilization of these pectins, thus playing a vital role in the structural integrity of plant tissues.

### Step 3: Analyze the Relationship Between A and R
Now, we need to determine if the reason supports the assertion.
- **Connection**: Since calcium is indeed required for the synthesis of the middle lamella, and the middle lamella is crucial for the structure of meristematic and differentiating tissues, the reason provides a valid explanation for the assertion.

### Conclusion
Both the assertion and the reason are true, and the reason correctly explains the assertion. Therefore, we can conclude that both A and R are true, and R is the correct explanation of A.

### Final Answer
- Assertion (A) is true.
- Reason (R) is true.
- R is the correct explanation of A.

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