Tooth decay is caused by the presence of a base.
a. True
b. False

Hint: As we know that tooth decay is caused by the small pieces and bits of food that are mainly accumulated on the hard tissues that are present on the teeth, like that of enamel. And the bacteria which is responsible for decay of our tooth is Streptococcus mutans.

Complete step by step answer:
- As we know that tooth decay is caused by the degradation of the food debris that is basically stuck in our teeth, mainly by the action of bacteria. Most of us have faced this problem of tooth decay or cavities.
- It is found that when food debris gets stuck in enamel or dentin in the form of carbohydrates, they are attacked by bacteria. And with increasing time the enamel of the teeth gets destroyed, that basically creates cavity and changes the colour of the tooth.
- There are simple sugars also found in food, that are also the primary source of bacteria, that are found to be further consumed by the bacteria and hence changes to an acidic compound which causes caries.
So the correct answer is “B”:

Note: - We should use toothpastes in order to brush our teeth regularly. As these are found to contain a mild amount of base in their components. But still it is found that toothpastes do not cause any degeneration of our tooth.