Question

Tooth decay starts when the pH of the mouth is lower than 5.5
a) Name the following:-
i) The hardest substance in the human body.
ii) The chemical compound of which it is made.
b) How does the use of toothpaste prevent tooth decay?​

Answer 1

Answer:

the hardest substance in the human body

Answer 2

a

1) The hardest part of body is Tooth enamel

2) It is made of mineral calcium phosphate,

b the toothpaste is of basic in nature and it react with acid present in our mouth