Answer:
b. because it explains how rocks are constantly changing from one type to another
Step-by-step explanation:
The rock cycle is very important for the Earth. It is a cycle that gives us explanation how the rocks change over time, and how each type of the rocks is formed, or destroyed. The rocks are providing the basis of the terrestrial life on the planet, as they are the ones that form the land masses. They are the ones that provide the minerals, and they are the ones that give the parent material for the soils. The rock cycle is a process that is continuing for over 2 billion years now, and it seems that it will continue to go on for much more time in the future. Basically, the magma from the mantle layer comes out on the surface or near it, cools off, and forms rocks. The rocks then experience changes over the course of millions of years. Eventually, the rocks will come in a situation to be subducted, returning to the mantle, get melted, thus recycled, and eventually coming back on the surface as magma or lava.