Select ONE entry for each blank from the corresponding column of choices. Fill ALL BLANKS in the way that best completes the text.
that sandstone arches like Utah’s Rainbow Bridge are the result of gravity and not wind and/or rain. They created sandstone cubes in the lab and then exposed them to conditions that
the effects of erosion; as parts of the cubes washed away, pressure increased on the remaining cubes, eventually reaching a point where the grains became stable by locking together.