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Question
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 reach the part F in the lower part of tooth which contains nerves and blood vessels. The 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, and (ii) part D, of tooth known as?
(c) By what name are the holes E in the tooth known?
(d) Name the part F of the tooth.
(e) What will happen if organisms A reach part F of the tooth known?
Solution
(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.
(e) When bacteria (organism A) reaches the pulp (part F) of the tooth, it irritates the nerve endings and causes toothache.
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