Explain how Eli Lilly, an American company produced insulin by recombinant DNA technology.

Explanation

### Step-by-Step Solution:

1. **Understanding Insulin**:
- Insulin is a peptide hormone produced by the beta cells of the pancreas. It plays a crucial role in regulating blood sugar levels and preventing diseases like diabetes mellitus.

**Hint**: Remember that insulin is essential for glucose metabolism and is naturally produced in the body.

2. **Need for Artificial Production**:
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