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).
Achondroplasia is a genetic disorder affecting bone development that results in short-limb dwarfism. 1  Achondroplasia is the most common form of short-limb dwarfism, a disorder in which bone tissue does not develop properly, especially the long bones of the arms and legs.chondroplasia is a genetic disorder affecting bone development that results in short-limb dwarfism. 1  Achondroplasia is the most common form of short-limb dwarfism, a disorder in which bone tissue does not develop properly, especially the long bones of the arms and legs.