[A]: In low degree smoking is helpful
[R]: In low doses, nicotine stimulates con- duction of nerves impulses & relaxes the muscles

Options

A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false

Answer

**Step-by-Step Solution:**

1. **Understanding the Statement [A]:** The statement claims that "In low degree smoking is helpful." This suggests that smoking, when done in moderation, may have some beneficial effects.

2. **Analyzing the Reason [R]:** The reason provided states that "In low doses, nicotine stimulates conduction of nerve impulses & relaxes the muscles." This indicates that nicotine, a primary component of tobacco, has certain physiological effects.

3. **Exploring the Effects of Nicotine:**
- **Stimulation of Nerve Impulses:** Nicotine acts as a stimulant. It enhances the conduction of nerve impulses, which can lead to increased alertness and awareness.
- **Muscle Relaxation:** Additionally, nicotine has muscle-relaxing properties, which can contribute to a feeling of relaxation.

4. **Evaluating the Relationship Between [A] and [R]:**
- The reasoning provided in [R] supports the claim made in [A]. If nicotine indeed stimulates nerve impulses and relaxes muscles, it provides a biological basis for the assertion that low-level smoking can be helpful.

5. **Conclusion:** Both statements [A] and [R] are correct, and the reasoning explains why the initial statement is valid. Therefore, we can conclude that the answer is correct.

**Final Answer:** Both [A] and [R] are true, and [R] correctly explains [A].

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