Plasma membrane exhibits for external substances -

Options

A. Impermeability
B. Selective Semipermeability
C. Permeability
D. None of these

Answer

To answer the question regarding what the plasma membrane exhibits for external substances, we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Understanding the Plasma Membrane**: The plasma membrane is a biological membrane that separates and protects the interior of the cell from the external environment. It plays a crucial role in regulating what enters and exits the cell.

2. **Defining Key Terms**:
- **Impermeability**: This means that no substances can pass through the membrane at all.
- **Permeability**: This indicates that substances can pass freely through the membrane.
- **Selective Permeability**: This allows certain substances to pass while restricting others.
- **Semi-permeability**: This typically refers to allowing the passage of solvent molecules while restricting solute molecules.

3. **Identifying the Correct Characteristic**: The plasma membrane is not completely impermeable, as it does allow some substances to pass through. It is also not fully permeable, as it does not allow all substances to pass freely. Instead, it exhibits selective permeability, which means it selectively allows certain molecules to enter or exit the cell while blocking others.

4. **Conclusion**: Based on the definitions and characteristics of the plasma membrane, the correct answer to the question is that the plasma membrane exhibits **selective permeability** for external substances.

### Final Answer:
The plasma membrane exhibits **selective permeability** for external substances.

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