Assertion : When plant cells are placed in highly concentrated sugar or salt solution, they get plasmolysed.
Reason : Highly concentrated sugar or salt acts as hypotonic solution which leads to exosmosis.

Options

A. If both Assertion and Reason are true and Reason is correct explanation of Assertions.
B. If both Assertion and Reason are true but Reason is not correct explanation of Assertion.
C. If Assertion is true but Reason is false.
D. If both Assertion and Reason are false.

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that when plant cells are placed in a highly concentrated sugar or salt solution, they get plasmolyzed. Plasmolysis is the process where the cell membrane pulls away from the cell wall due to loss of water.

2. **Defining the Solution**: A highly concentrated sugar or salt solution has a high concentration of solute (sugar or salt) compared to the inside of the plant cell, which has a lower concentration of solute.

3. **Identifying the Type of Solution**: In this scenario, the external solution is hypertonic relative to the plant cell. A hypertonic solution has a higher concentration of solutes compared to the inside of the cell.

4. **Understanding Exosmosis**: When plant cells are placed in a hypertonic solution, water moves out of the cell to the area of higher solute concentration (the external solution). This movement of water out of the cell is known as exosmosis.

5. **Consequences of Exosmosis**: As water exits the cell, the cell loses turgor pressure and begins to shrink. This shrinkage of the cell is what we refer to as plasmolysis.

6. **Evaluating the Reason**: The reason provided states that highly concentrated sugar or salt acts as a hypotonic solution, which is incorrect. A hypotonic solution has a lower concentration of solutes compared to the inside of the cell, which would cause water to enter the cell, not exit.

7. **Conclusion**: Therefore, the assertion is true (plant cells do get plasmolyzed in concentrated solutions), but the reason is false (the solution is hypertonic, not hypotonic).

**Final Answer**: The correct option is that the assertion is true, but the reason is false.

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