Which of following is the mechanically formed sedimentary rock?

1. Limestone
2. Dolomite
3. Sandstone
4. Chert

The cyclic process of changing the form of rocks is called

1. Natural cycle
2. Rock cycle
3. Stone cycle
4. Metamorohism

Which of the following process is responsible for the formation of igneous rocks?

1. Sedimentation
2. Metamorphism
3. Cooling & solidification of magma
4. Lithification

Rina has the hobby of collecting different stones from different areas wherever she travels. Those stones are having different colour and texture. Some are hard and some are soft. What is the reason for such difference?