Final answer:
The subject of this question is Geography. Sedimentary rocks are formed through the deposition and cementation of particles carried in air or water, resulting from the weathering and erosion of rocks on the Earth's surface. The size and shape of grains within sedimentary rocks can provide insights into their history.
Step-by-step explanation:
The subject of this question is Geography.
According to the information provided, the student is asking about the characteristics and formation of sedimentary rocks, specifically clastic sedimentary rocks. Sedimentary rocks are formed through the deposition and cementation of particles carried in air or water, resulting from the weathering and erosion of rocks on the Earth's surface. Clastic sedimentary rocks are formed from pre-existing rocks that undergo weathering and are carried by water or air until they settle in a lower area.
The provided information also mentions that the size and shape of grains within sedimentary rocks can provide insights into their history. Well-sorted sediment indicates that the particles traveled a far distance before being deposited, while poorly sorted sediment is closer to its source. Grains with smooth edges are considered well-rounded and have traveled a far distance, while grains with sharp edges are angular and have not traveled far.