text: <unk> s are cells that deposit enamel, the hard outer most layer that forms the chewing surface.<unk> s are cells which secrete the enamel proteins enamelin and amelogen which will later mineralise to form enamel on teeth, the strongest substance in the human body. Each<unk>  is approximately 4 micrometers in diameter, 40 micrometers in length and has a hexagonal cross section. The secretory end of the<unk>  ends in a six sided pyramid like projection known as the Tomes' process. The angulation of the Tomes' process is significant in the orientation of enamel rods.<unk> s are derived from oral epithelium tissue of ectodermal origin. Their differentiation is a result of signalling from the ectomesenchymal cells of the dental papilla. The<unk> s will only become fully functional after the first layer of dentine has been formed, as such dentine is a precursor to enamel.<unk> s control ionic and organic compositions of enamel.  They adjust their secretory and re absorptive activities to maintain favorable conditions for biomineralization.
option_0: Ameloblast
option_1: Immunoblast
option_2: Trophoblast
option_3: Chondroblast
option_4: Megakaryoblast
option_5: Lymphoblast
option_6: Histiocyte
option_7: Normoblast