__________ is an example of medicine extracted from the bark of a plant.

Explanation

**Step-by-Step Text Solution:**

1. **Identify the Question**: The question asks for an example of a medicine that is extracted from the bark of a plant.

2. **Recall Relevant Information**: One well-known medicine that is derived from the bark of a plant is quinine.

3. **Source of Quinine**: Quinine is specifically extracted from the bark of the cinchona tree.

4. **Age of the Tree**: The cinchona tree from which quinine is extracted is typically around 7 to 8 years old, as this age provides the maximum yield of quinine.

5. **Function of Quinine**: Quinine is recognized for its medicinal properties, particularly as an anti-malarial drug, which means it is used to treat malaria.

6. **Final Answer**: Therefore, the answer to the question is: **Quinine**.

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