Rennin: Milk protein: : Gastric lipase :_____.

Explanation

To solve the analogy "Rennin: Milk protein: : Gastric lipase : _____", we need to understand the relationship between the first pair of terms and then apply that relationship to the second term.

### Step-by-Step Solution:

1. **Identify the Function of Rennin**:
- Rennin is an enzyme that acts on milk proteins. Its primary function is to coagulate milk, which means it helps in breaking down milk proteins.

2. **Identify the Function of Gastric Lipase**:
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