Which of the following is an Organic Rock?
Answer: (2). Coal
Rocks are naturally occurring solid substance which is found at the outer surface of earth known as Lithosphere. Many minerals and metals are found in rocks, like mica graphite, etc, Rocks are known from the ancient time as Stone age. At that time, rocks are used for making tools. The major rocks are of mainly three types: Igneous, Sedimentary, and Metamorphic rocks.
Geologically the rocks are classified on the basis of their composition, constituent particles, chemical composition.
Organic sedimentary rocks are made up of decayed living organisms, trees, and other organisms build up and compacted by sediment. Coal is the best example of organic rock which is made from long dead vegetation crushed by the thick layer of sediment and chemically altered through heat and pressure.