What type of sedimentary rock is formed by the accumulation of plant remains?

Coal is a type of sedimentary rock that forms primarily from the accumulation and compaction of plant material, particularly in swampy environments where conditions prevent complete decay. Over millions of years, layers of plant remains accumulate and undergo biochemical processes that transform them into peat. As burial depth increases, heat and pressure gradually convert peat into coal through coalification. This transformation results in a dense, carbon-rich rock that can be mined for energy.

In contrast, sandstone is formed from sand-sized particles; shale results from clay minerals and silt; limestone primarily consists of calcium carbonate from marine organisms. None of these types of sedimentary rock are derived from plant material, which distinctly sets coal apart as the correct answer.