For geology, a rock is a cohesive solid that is made up of one or more minerals and there are three different types: igneous (a), metamorphic (c) and sedimentary (b).
- Igneous rocks are those that have been formed by the solidification of magma or lava.
- Metamorphic rocks are formed when igneous or sedimentary rocks are subjected during and after long periods of time to heat, humidity and / or pressure.
- On the other hand, sedimentary rocks are formed as a result of the action of atmospheric agents on pre-existing rocks.
- Being subjected to the action of different agents, rocks can change over time, this cycle is known as the petrogenetic cycle and includes stages of weathering, erosion and sedimentation.
Therefore, we can conclude that igneous (a), metamorphic (c), and sedimentary (b) are the letters that identify a type of rock.
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