What are antibiotics? Name the organism from which Penicillin was first extracted.

Explanation

### Step-by-Step Solution:

1. **Definition of Antibiotics**:
- Antibiotics are chemical substances that are produced by certain microorganisms. They have the ability to kill or inhibit the growth of other microorganisms, particularly those that cause diseases (pathogens).

2. **Etymology of the Term**:
- The term "antibiotic" is derived from two parts: "anti" meaning against, and "bio" meaning life. Thus, it refers to substances that act against living organisms, specifically those that cause diseases.

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