Epithelial tissue lining a blood vessel is known as ……………..

Explanation

**Step-by-Step Solution:**

1. **Understanding Epithelial Tissue**: Epithelial tissue is one of the four main types of tissues in the body. It serves various functions, including protection, absorption, secretion, and sensation.

2. **Identifying the Type of Epithelial Tissue**: The question specifically asks about the epithelial tissue that lines blood vessels. In the circulatory system, different types of epithelial tissues are present, but the one that lines the blood vessels is specialized.

3. **Recognizing the Specific Epithelial Tissue**: The epithelial tissue lining blood vessels is known as "endothelium." It is a type of simple squamous epithelium, which means it consists of a single layer of flat cells.

...