Fig. 5.1 shows a decaying tooth. [Figure 5.1]

1. (a)Name the type of tooth shown.[1]
2. (b)Name two structures that are found in region K. 1 2[2]
3. (c)Explain the causes of the decay shown in Fig. 5.1.[4]
4. (d)(i)Two different regions were studied to see the effect of fluoridation of drinking water on the mean number of decayed teeth in children living in those regions. In region L, the percentage of children drinking fluoridated water gradually increased over a 30-year period. In region M, no fluoride was added to the drinking water over the same period. Table 5.1 shows the mean number of decayed teeth per child in each region. It also shows the percentage of children drinking fluoridated water in region L. Table 5.1 region L region M date percentage mean number mean number 1970 28 3.9 2.1 1980 32 3.3 1.9 1990 38 2.7 1.8 2000 60 1.2 1.6 State the effect of adding fluoride to the water supplies in region L.[1]
5. (d)(ii)Suggest three possible reasons for the results shown for children in region M. 1 2 3[3]

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