A nerve fibre during resting stage is

Options

A. more permeable to `Na^+`
B. more permeable to `K^+`
C. equally permeable for `Na^+ and K^+`
D. less permeable to `K^+`

Explanation

To answer the question "A nerve fibre during resting stage is," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Resting Potential**:
- A nerve fiber at rest is said to be in a state of resting potential. This is the electrical potential difference across the membrane when the neuron is not transmitting an impulse.

2. **Membrane Permeability**:
- During the resting stage, the nerve fiber membrane is more permeable to potassium ions (K+) than to sodium ions (Na+). This means that potassium ions can move more freely across the membrane compared to sodium ions.

3. **Ion Concentration**:
- Inside the nerve fiber (intracellularly), there is a higher concentration of potassium ions, while outside the nerve fiber (extracellularly), there is a higher concentration of sodium ions. This difference in ion concentration is crucial for the resting potential.

4. **Charge Distribution**:
- Due to the movement of ions, the inside of the nerve fiber becomes negatively charged relative to the outside. The extracellular environment is positively charged because of the higher concentration of sodium ions.

5. **Conclusion**:
- Therefore, during the resting stage, a nerve fiber is characterized by being more permeable to potassium ions and nearly impermeable to sodium ions.

### Final Answer:
The correct answer is that a nerve fibre during the resting stage is **more permeable to potassium**.

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