102. When a person eats sugary food, then organisms A present in his mouth act on sugar to produce a substance B. The substance B first dissolves the calcium salts from the top part C of the tooth and then from its middle part D forming holes E. These holes ultimately act on the part F in the lower part of the tooth which contains nerves and blood cells. Substance B irritates the nerve endings inside the tooth causing toothache. (a) What are (i) organisms A, and (ii) substance B? (b) What are (i) part C (ii) part D, of the tooth known as? (c) By what name are the holes E in the tooth known as? (d) Name the part F of the tooth? (e) What will happen if organisms A reach F part of tooth?
(a) (i) Organism A is bacteria and (ii) substance B is acid. (b) (i) Part C is the tooth enamel and (ii) part D is the dentine of the tooth. (c) The small holes, E, are known as cavities. (d) F is the pulp of the tooth.
