What characterizes stratified epithelium?

• A. Two or more layers
• B. One layer
• C. No layers
• D. All of the above

Answer: (A)

Stratified epithelium is defined by its layered structure—two or more cell layers stacked from the basement membrane to the surface. This multilayer organization provides strong protection against abrasion, friction, and chemical stress, which is why it lines areas subject to wear, such as the skin and the mucous membranes of the mouth and esophagus. The deepest layer sits on the basement membrane, and as cells migrate outward they can become flatter or keratinized, depending on the tissue’s needs. In contrast, simple epithelium has a single cell layer and is typically specialized for absorption, secretion, or diffusion. So the key feature is having two or more layers.