What are epithelial tissues? What is their function and how is that function associated with the features of the tissue?

Explanation

Epithelial tissues, also called epithelia, are tissues specialized in covering the external and internal surfaces of the body. The general function of the epithelium is to provide protection and impermeability (or selective permeability) to structure it covers. This is the reason for the epithelium’s typical feature: the juxtaposition of layers of very close cells with little or no intercellular space between each two neighbouring cells.