Coal forms from the accumulation of plant debris, usually in a swamp environment. When plant debris dies and falls into the swamp the standing water of the swamp protects it from decay. Swamp waters are usually deficient in oxygen, which would react with the plant debris and cause it to decay.
Porokeratosis is generally considered to be a benign condition though malignant transformation has been seen in all but the punctate variety, necessitating regular followup of patients with porokeratosis (Maubec et al., 2005; Sasson & Krain, 1996).
Keratosis pilaris is a very common and completely harmless skin condition. In the population as a whole, keratosis pilaris may affect as many as one person in three.he groups of small spiky bumps are most common on the backs of the upper arms and on the fronts of the thighs. Sometimes keratosis pilaris also affects the back and chest and, in less common forms, the face and eyebrows as well. Some redness may appear around the small spiky bumps.