Question

The enamel of the teeth contains:
$A)$Fluorapatite
$B)$Chlorapatite
$C)$Apatite
$D)$Calcium monohydrogen phosphate

Answer 1

Fluorapatite is a phosphate mineral. Fluorapatite is a hard crystalline solid. Although samples can have various colors, the pure mineral is colorless, as expected for a material lacking transition metals. Along with hydroxyapatite, it can be a component of tooth enamel.

Complete answer: Enamel is the hardest substance in the human body, and it covers the external surface of your teeth. It is made generally of a very hard mineral called calcium phosphate. Dentin makes up the layer just underneath your tooth's enamel. It comprises of living cells that discharge a mineral substance.
Fluorapatite is found in the teeth of sharks and different fishes in fluctuating fixations. It is additionally present in human teeth that have been presented to fluoride particles, for instance, through water fluoridation or by utilizing fluoride-containing toothpaste. The presence of fluorapatite forestalls tooth rot or dental caries.
Fluorapatite has a basic pH of $4.5$ , along these lines it makes tooth structure more impervious to extra caries attack. It has a gentle bacteriostatic property also, which helps decline the multiplication of Streptococcus mutans, the transcendent bacterium identified with dental caries.
So, the correct answer is $A)$ fluorapatite.

Note:
Fluorapatite as a naturally occurring impurity in apatite generates hydrogen fluoride as a byproduct during the production of phosphoric acid, as apatite is digested by sulfuric acid. The hydrogen fluoride byproduct is now one of the industrial sources of hydrofluoric acid, which in turn is used as a starting reagent for synthesis of a range of important industrial and pharmaceutical fluorine compounds.