Is epithelium vascularized? How do nutrients and oxygen reach epithelium? Why is this feature an important evolutionary acquisition?

Explanation

### Step-by-Step Solution:

1. **Understanding Vascularization of Epithelium:**
- The first part of the question asks whether epithelium is vascularized. The answer is **no**, epithelium is not vascularized, meaning it does not contain blood vessels.

2. **Nutrient and Oxygen Supply:**
- Since epithelium lacks a direct blood supply, nutrients and oxygen reach epithelial cells through the **underlying connective tissue**. The connective tissue has blood vessels that supply the necessary nutrients and oxygen.

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