Assertion: The movement of ions into or out of the cells is usually called flux.
Reason: The entry or exit of ions to and from the symplast, is an active process.

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, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "The movement of ions into or out of the cells is usually called flux."
- **Analysis**: This statement is true. The term "flux" refers to the movement of ions (or other substances) across cell membranes, which can be either influx (movement into the cell) or efflux (movement out of the cell).

2. **Understanding the Reason**:
- The reason states that "The entry or exit of ions to and from the symplast is an active process."
- **Analysis**: This statement is also true. The movement of ions across cell membranes, especially into the symplast (the living part of the plant cells), often requires energy, making it an active transport process.

3. **Evaluating the Relationship**:
- We need to determine if the reason correctly explains the assertion.
- While both statements are true, the reason does not provide a direct explanation for the assertion. The assertion discusses the general concept of ion movement (flux), while the reason specifically addresses the transport mechanism related to the symplast.

4. **Conclusion**:
- Both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
- Therefore, the answer to the question is: "Both assertion and reason are true, but reason is not the correct explanation of assertion."

### Final Answer:
Both assertion and reason are true, but reason is not the correct explanation of assertion.

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