The osomotic pressure `pi` depends on the molar concentration of the solution `(pi=CRT)`. If two solutions are of equal solute concentration and, hence, have the same omotic pressure, they are said to be isotonic. If two solutions are of unequal osmotic pressures, the more concentrated solution is said to be hypertonic and the more diluted solution is described as hypotonic.
Osmosis is the major mechanism for transporting water upward in the plants. Answer the following questions:
A plant cell shrinks when it is kept in:

Options

A. Hypotonic solution
B. Hypertonic solution
C. Isotonic solution
D. Pure water

Explanation

To determine the condition under which a plant cell shrinks, we need to understand the concept of osmotic pressure and the behavior of cells in different solutions.

### Step-by-Step Solution:

1. **Understanding Osmosis**: Osmosis is the movement of water across a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration.

2. **Identifying Solution Types**:
- **Isotonic Solution**: A solution that has the same osmotic pressure as the cell's interior. The cell remains the same size because there is no net movement of water.
- **Hypertonic Solution**: A solution that has a higher osmotic pressure (or higher solute concentration) than the cell's interior. Water moves out of the cell, causing it to shrink.
- **Hypotonic Solution**: A solution that has a lower osmotic pressure (or lower solute concentration) than the cell's interior. Water moves into the cell, causing it to swell.

3. **Analyzing the Question**: The question asks when a plant cell shrinks. For a plant cell to shrink, it must be placed in a solution that has a higher osmotic pressure than the fluid inside the cell.

4. **Conclusion**: Therefore, a plant cell shrinks when it is kept in a **hypertonic solution**.

### Final Answer:
A plant cell shrinks when it is kept in a hypertonic solution.

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