Question

How epithelial tissue keeps different body systems separate?

Answer 1

The cells of epithelial tissue pack tightly together and form continuous sheets that serve as linings in different parts of the body. 
Epithelial tissue serve as membranes lining organs and helping to keep the body's organs separate, in place and protected. 
Some examples of epithelial tissue are the outer layer of the skin, the inside of the mouth and stomach, and the tissue surrounding the body's organs.

Answer 2

The cells of epithelial tissue pack tightly together and form continuous sheets that serve as linings in different parts of the body. 
Epithelial tissue serve as membranes lining organs and helping to keep the body's organs separate, in place and protected. 
Some examples of epithelial tissue are the outer layer of the skin, the inside of the mouth and stomach, and the tissue surrounding the body's organs.