The thin layer of epithelial tissue in the small intestines works somewhat like a cell membrane. How does its structure relate to its function in the digestive system?

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?