The pit does not have any magical properties. What turns the guac brown is the air. If you can keep air from touching the guac then it will stay green. The pit will keep a portion away from the air, but what is more affective is to put plastic wrap over it and push it right down onto the surface.
Denuded skin is just another way of saying that the top layer (epidermis) of skin is gone...either from friction (abrasion or tear), trauma (tape burns), or severe rashes, or from a stage II pressure ulcer.
The friction of a shear stress at the edges of the plate can cause earthquakes. Confining Stress. When stress is applied to all sides of the crust, confining stress occurs. When this happens, the crust compacts, which makes it look smaller. If the stress is too much for the crust to handle, the crust can fracture from the inside.