The percentage of cell surface that is impenetrable for ions is

Options

A. 00.1
B. 99.9
C. 90
D. 73

Explanation

To solve the question regarding the percentage of the cell surface that is impenetrable for ions, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the percentage of the cell surface that does not allow ions to pass through. This means we are looking for the impenetrable portion of the cell surface.

2. **Know the Structure of the Cell Membrane**: The cell membrane, also known as the plasma membrane, is selectively permeable. This means that it allows certain substances, such as ions, to pass through while blocking others.

3. **Identify the Penetrable Area**: According to the information provided, less than 0.1% of the plasma membrane has pores that allow ions to pass through. This indicates that this small percentage is the penetrable area.

4. **Calculate the Impenetrable Area**: If less than 0.1% of the cell surface is penetrable, then the impenetrable area can be calculated as follows:
- Total surface area = 100%
- Penetrable area = 0.1% (or less)
- Impenetrable area = Total surface area - Penetrable area
- Impenetrable area = 100% - 0.1% = 99.9%

5. **Select the Correct Option**: Based on the calculation, we find that 99.9% of the cell surface is impenetrable for ions. Therefore, the correct answer is option B: 99.9%.

### Final Answer:
The percentage of cell surface that is impenetrable for ions is **99.9%**.

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