Which of the following controls permeability

Options

A. Cell membrane
B. Cell wall
C. Protoplasm
D. Cytoplasm

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which structure controls permeability. Permeability refers to the ability of substances to pass through a membrane.

2. **Identifying the Options**: The options given are:
- Cell membrane
- Cell wall
- Protoplasm
- Cytoplasm

3. **Analyzing Each Option**:
- **Cell Membrane**: This is a biological membrane that surrounds the cell. It is known for its selective permeability, meaning it allows certain substances to pass while blocking others.
- **Cell Wall**: This is a rigid outer layer found in plant cells, fungi, and some bacteria. It provides structural support but is not selectively permeable.
- **Protoplasm**: This term refers to the living contents of a cell, including the cytoplasm and the nucleus. It does not control permeability.
- **Cytoplasm**: This is the gel-like substance within the cell membrane, but it does not control permeability either.

4. **Conclusion**: The structure that controls permeability is the **cell membrane** (also known as the plasma membrane). It regulates what enters and exits the cell, thus maintaining the internal environment.

5. **Final Answer**: The correct answer is the **cell membrane**.

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