All or none law is associated with

Options

A. Muscle fibre
B. Neuron
C. Uriniferous tubule
D. Both A and B.

Answer

**Step-by-Step Solution:**

1. **Understanding the All or None Law**: The all or none law states that a muscle fiber or a neuron will either fully respond to a stimulus or not respond at all. There is no partial response.

2. **Application to Muscle Fibers**: In the muscular system, when a muscle fiber receives a stimulus that exceeds a certain threshold, it will contract fully. If the stimulus is below this threshold, the muscle will not contract at all. This principle ensures that muscle contractions are efficient and effective.

3. **Application to Neurons**: Similarly, in the nervous system, neurons operate under the all or none principle. When a neuron is stimulated and reaches a certain threshold, it will fire an action potential and transmit an impulse. If the stimulus does not reach this threshold, the neuron will not fire.

4. **Identifying the Structures**: The question asks which structures are associated with the all or none law. Based on the explanations, both muscle fibers and neurons exhibit this principle.

5. **Conclusion**: Therefore, the correct answer to the question is that the all or none law is associated with both muscle fibers and neurons. This leads us to the conclusion that the correct option is both A (muscle fiber) and B (neuron).

**Final Answer**: The all or none law is associated with both muscle fibers and neurons (Option 4).

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