Final answer:
Sedimentary rocks can form through various processes, including clastic sedimentation, chemical precipitation of salts, and the accumulation of organic debris. These rocks can provide insights into early Earth conditions.
Step-by-step explanation:
Sedimentary rocks can form in several ways. Clastic sedimentary rocks form when pre-existing rocks undergo chemical and mechanical weathering and are then carried by wind, water, or ice to a lower area where they settle and form layers. Chemical sedimentary rocks form when water containing dissolved salt evaporates, leaving behind salt as a solid mineral called a precipitate. Organic sedimentary rocks form from the accumulation of organic debris, such as coal or oil. These rocks can provide evidence of early Earth conditions.