Sedimentary rock ____ A) forms below the crust B) is made from cooling magma C) usually forms horizontal layers D) doesn't contain fossils

Sedimentary rock is rock that is formed on earth's surface from the eroded or weathered away remains of other types of rock.  The bits and pieces that are worn away from these other types of rocks are collected in horizontal layers of sediments.  Layer after layer of sediments pile up, exerting pressure on the underlying layers.  Finally, there is enough pressure to press the sediments into rocks. Sandstone and shale are two examples of sedimentary...

Sedimentary rock is rock that is formed on earth's surface from the eroded or weathered away remains of other types of rock.  The bits and pieces that are worn away from these other types of rocks are collected in horizontal layers of sediments.  Layer after layer of sediments pile up, exerting pressure on the underlying layers.  Finally, there is enough pressure to press the sediments into rocks. Sandstone and shale are two examples of sedimentary rock.  Fossils are found often encased within layers of sedimentary rock. So C, "usually forms horizontal layers," is the best answer. 

I think I addressed all the answer choices, but just in case:  A) sedimentary rock is formed at the surface of the earth's crust, B) sedimentary rock is made from sediments, not cooling lava, C) does form horizontal layers, and D) often contains fossils, which are the dead remains of once living animals and plants.

Steno's Law of Original Horizontality states that most sediments, when originally formed, were laid down horizontally. ... [W]e know that sedimentary rocks that are not horizontal either were formed in special ways or, more often, were moved from their horizontal position by later events, such as tilting during episodes of mountain building. ("Rocks and layers," usgs.gov)