alleryTooth enamel is made of:
ACalcium phosphate
BCalcium carbonate
CCalcium sulphate
DSodium chloride
Answer & Solution
Correct answer: A. Calcium phosphate
1. Tooth enamel is largely hydroxyapatite: Ca₅(PO₄)₃(OH) — a calcium phosphate.
2. Hardest substance in the human body.
3. Acids from bacteria fermenting sugar dissolve enamel → cavities. Toothpaste (basic) helps neutralise this.
_Source: syllabus Science Ch 2 §2.3 Tooth Decay_
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