Chapter 18, Problem 10A

Summary Introduction

Introduction:

The tooth is the hard structure present n mouth that aids in the mastication and breaking down of the food in smaller pieces. The outer most part of the tooth is made up of a substance called enamel, which is rich in calcium and phosphate.

Answer to Problem 10A

Option (B).

Explanation of Solution

Explanation for correct answer:

Option (B) bacteria feeding on sugar and producing acids. The tooth is made up of calcium and phosphate. The calcium and phosphate can react with acids. The bacteri that produces acids as a byproduct can damage tooth as the acid produced by the bacteria may react with enamel causing cavities in the enamel.

Explanation for incorrect answer:

Option (A) lysogenic virus infecting living cells of tooth. The enamel covers the soft and living part of the tooth, so, it is not possible for the virus to infect living cells of tooth. Hence, this is an incorrect answer.

Option (C) excess of vitamin K production. The vitamin K increases the saliva buffering capacity in the mouth, which can lower the acidity level in the mouth, hence, preventing tooth decay. Hence, this is an incorrect answer.

Option (D) nitrogen fixing bacteria producing ammonia. The ammonia is a basic substance and this would not cause tooth decay as it is not corrosive for calcium. So, this is an incorrect answer.