___________ a fungus produces penicillin.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the name of a fungus that produces penicillin.

2. **Identifying Penicillin**: Penicillin is known as an antibiotic, which is a substance that can kill or inhibit the growth of bacteria.

3. **Identifying the Fungus**: The specific fungus that is known for producing penicillin is called *Penicillium notatum*.

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