(A) : The quiescent centre act as a reservoir of relatively resistant cells which constitute a permanent source of active initials.
(R ): The cells of the inactive region of quiescent centre becomes active when the previous active initial get damaged

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 true but R is false
D. Both (A) and (R ) are false

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the quiescent center acts as a reservoir of relatively resistant cells that serve as a permanent source of active initials.
- This means that the quiescent center contains cells that are not actively dividing but can become active when necessary.

2. **Understanding the Reason**:
- The reason provided explains that the cells in the inactive region of the quiescent center become active when the previously active initial cells are damaged.
- This indicates that the quiescent center has a backup system to ensure that cell division can continue if the active cells are compromised.

3. **Defining the Quiescent Center**:
- The quiescent center is a specific region found in the root tip of vascular plants, particularly in the apical meristem.
- It consists of a small group of cells (up to 1000) that divide very slowly or not at all, making them relatively resistant to damage.

4. **Function of the Quiescent Center**:
- The primary function of the quiescent center is to maintain a reservoir of cells that can be activated when the surrounding active cells are damaged.
- This ensures that the plant can continue to grow and develop even when some cells are lost.

5. **Evaluating the Truth of the Statements**:
- Both the assertion and the reason are true. The quiescent center does act as a reservoir of resistant cells, and these cells can become active when needed, particularly when active initial cells are damaged.

6. **Conclusion**:
- Since both the assertion and the reason are true, and the reason correctly explains the assertion, we conclude that the answer is: Both assertion and reason are true, and the reason is a correct explanation of the assertion.