$\begin{array}{1 1} (a)\; \text{Formed at earth's surface by the accumulation and cementation of fragments of earlier rocks} \\ (b)\; \text{Due to change in temperature,sediments gets deposited} \\ (c)\; \text{Melting of rocks} \\ (d)\; \text{Forms through the cooling and solidification of magma or lava. } \end{array}$
