How sedimentary rocks are classified. explain …

Sedimentary rocks are formed by the deposition and subsequent cementation on the material at the Earth’s surface within the bodies of water. 
Sedimentation is the combined name for all the processes that cause organic and mineral particles to get settle. The particle that helps in forming the sedimentary rock is called sediment. This sediment is formed with the help of erosion and weathering from the source area and which is then transported to the deposition place by the wind, water, ice and glaciers which are agents of denudation.
The sedimentary rocks are classified into three different types: Organic, Clastic and Chemical Sedimentary Rocks.
 

Organic Sedimentary Rocks

This rock type mainly comprises of coal and limestones which is formed due to accumulation and deposition of dead plants and animals in rock layers.

Clastic Sedimentary Rocks

This type of rock is formed when rock layers are formed due to the mechanical weathering of different rock types.

Chemical Sedimentary Rocks

This rock type is formed when there is a chemical reaction between minerals, present in rock forms cools down as precipitate and converts to rock form over a period of time.