How are sedimentary rocks formed?

Sedimentary rocks are formed through the processes of accumulation and compaction of sediment over time. This involves the gradual layering of materials such as sand, silt, clay, and organic matter that settle out of water or are deposited by wind. As more layers of sediment accumulate on top, the weight of the upper layers exerts pressure on the lower layers, leading to compaction. Additionally, minerals precipitate from water, further cementing the sediment together to form solid rock.

This process is distinct from other rock formation processes. For example, the formation of igneous rocks occurs through the cooling and solidification of molten lava or magma, while metamorphic rocks are created from the alteration of existing rocks due to heat and pressure, rather than the accumulation of sediments. Therefore, the process described in the correct answer accurately captures how sedimentary rocks originate.