What type of sedimentary rock is formed from the accumulation of plant or animal remains?

The type of sedimentary rock that is formed from the accumulation of plant or animal remains is organic sedimentary rock. This category includes rocks like coal, which forms from compressed plant matter, and some types of limestone, which may originate from the accumulation of shells and coral. Organic sedimentary rocks are characterized by their composition, as they predominantly consist of biological material that has been compacted over time.

The formation process for organic sedimentary rocks involves biological activity, where plant and animal remains accumulate in a specific environment, often in wetlands or shallow marine areas. Over time, these remains are buried under layers of sediment, leading to lithification, or the process of becoming rock.

Clastic rocks, on the other hand, are formed from fragments of other rocks and minerals that have been weathered and eroded. Chemical sedimentary rocks result from the precipitation of minerals from solution, typically in evaporating environments, while biochemical rocks do involve biological processes but are primarily distinguished from organic rocks in that they are formed from inorganic minerals that were influenced by biological activity. Thus, the classification as organic reflects the predominant role that biological materials play in its formation.