Hard tissue made up of various salts. Enamel is the hardest substance in the human body and contains the highest percentage of minerals, 96%, with water and organic material composing the rest. The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. Enamel is formed on the tooth while the tooth is developing within the gum, before it erupts into the mouth. Once fully formed, it does not contain blood vessels or nerves. Remineralisation of teeth can repair damage to the tooth to a certain degree but damage beyond that cannot be repaired by the body. The maintenance and repair of
Sociology of human consciousness presumed evolutionary advantages of human reflectivity must be qualified or viewed as conditional. In sum, recent research, building on the work of George Herbert Mead, suggests that a sociological and social psychological perspective can be a point of departure with which to define and analyze certain forms of human consciousness, or more precisely, one class of consciousness phenomena, namely verbalized reflectivity: monitoring, discussing, judging and re-orienting and re-organizing self; representing and analyzing what characterizes the self, what self perceives, judges, could do, should do (or should not do)). The "hard problem" of consciousness can be approached fruitfully by beginning with