State whether the following statement is true or false.
A membrane which allows certain substances to pass, but does not allow others to pass through it is called a selectively permeable membrane.
A. True
B. False

Answer

To determine whether the statement "A membrane which allows certain substances to pass, but does not allow others to pass through it is called a selectively permeable membrane" is true or false, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition**: Begin by defining what a selectively permeable membrane is. A selectively permeable membrane is one that allows certain substances to pass through while restricting others.

2. **Consider Examples**: Think about examples of selectively permeable membranes. The most common example is the cell membrane (plasma membrane) of eukaryotic cells, which regulates the movement of ions, nutrients, and waste products.

3. **Analyze the Statement**: The statement describes a membrane that permits the passage of some substances but not others. This aligns perfectly with the definition of a selectively permeable membrane.

4. **Conclusion**: Since the statement accurately describes the nature of a selectively permeable membrane, we can conclude that the statement is true.

5. **Select the Correct Option**: Based on the analysis, the correct answer is Option A: True.

### Final Answer:
A. True

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