(a)[2]
Use label lines and labels on Fig. 4.1 to show an incisor tooth and a molar tooth.
(b)[5]
A healthy adult human has 32 teeth. (i) State how many teeth E has lost. (ii) State how many decayed teeth D has. (iii) Suggest two reasons for the difference in decayed teeth between D and E. (iv) Identify the tooth type that decays most often in Fig. 4.2.
(c)[2]
Describe the way bacteria contribute to tooth decay.