牙石中含70％-80％（），其余为有机成分和水。
参考答案：无机盐
负变位齿轮的齿顶会（）。
A．变尖
B．变宽
C．不变
Explain and distinguish between the following terms in relation to the doctrine of precedent in the Irish legal system:
(b) binding precedent and persuasive precedent. (6 marks)
