[A]: Ringing/Girdling experiments involved removal of all tissues outside endodermis from a woody stem.
[R]: The upper & lower part of the plant is at- tached by central xylem & phloem.

Options

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

Answer

To analyze the assertion and reason provided in the question, we will break down the concepts involved in the ringing (or girdling) experiments and their implications for plant physiology.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Ringing/Girdling experiments involved removal of all tissues outside the endodermis from a woody stem."
- In reality, girdling involves the removal of the phloem, which is the tissue responsible for the transport of food (sugars) in plants. The endodermis is not typically the focus of girdling; rather, it is the phloem that is removed.

2. **Evaluating the Assertion**:
- Since girdling does not involve the removal of all tissues outside the endodermis, the assertion is **false**. It specifically targets the phloem, not all surrounding tissues.

3. **Understanding the Reason (R)**:
- The reason states that "The upper & lower part of the plant is attached by central xylem & phloem."
- While it is true that xylem and phloem connect different parts of the plant, during girdling, the phloem is removed. This means that the connection for food transport between the upper and lower parts of the plant is disrupted.

4. **Evaluating the Reason**:
- Since the phloem is removed during girdling, the statement that the upper and lower parts of the plant are connected by both xylem and phloem is **false** in the context of girdling.

5. **Conclusion**:
- Both the assertion (A) and the reason (R) are false. Therefore, the correct answer to the question is that both A and R are false.

### Final Answer:
Both A and R are false.

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