Differentiate between muscle twitch and tetanus.

Explanation

**Step-by-Step Solution:**

1. **Definition of Muscle Twitch:**
- A muscle twitch is defined as an involuntary contraction of muscle fibers. It occurs when a motor neuron stimulates a muscle fiber, leading to a brief and rapid contraction.

2. **Causes of Muscle Twitch:**
- Muscle twitches can be caused by various factors, including nerve stimulation, fatigue, or damage to the nerves. They are typically harmless and can occur in various muscles of the body.

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