Interfaces in Object Oriented Programming Languages. An interface is a programming structure/syntax that allows the computer to enforce certain properties on an object (class). For example, say we have a car class and a scooter class and a truck class. Each of these three classes should have a start_engine() action.
The epidermis is the very outer layer of the skin that provides protection from bacteria (thanks to it's pH level), becoming overloaded with water (it's waterproof) and from heat loss. It has four of five distinct layers to achieve this.
The epidermis is the outermost layer of our skin. Its main purpose is protection. The epidermis is made of four main layers, or strata 1  : The stratum corneum is the thick, tough outer layer. 2  It is made mostly of dead cells that slough off constantly. 3  The stratum basale is comprised of new cells that are constantly dividing to replace the stratum corneum.