A geologist finds ripples preserved in ancient sedimentary rocks that look like ripples made by water in mud . He concludes that there was once water in that location that created the ripples . Why is this conclusion reasonable ?

The table below shows the elements that mainly comprise each of the four layers of earth: elements in layers layer main elements crust oxygen, silicon mantle iron, magnesium outer core iron, nickel inner core iron which of these elements make up the layer that is 0.2 to 1.1 percent of earth's total diameter?