$\begin{array}{1 1} \text{Ag can oxidised Zn and Cu } \\ \text{Ag can reduced $Zn^{2+}$ and $Cu^{2+}$ } \\ \text{Zn can reduced $Ag^{+} $ and $Cu^{2+}$ } \\ \text{Cu can oxidised Zn and Ag } \end{array} $