4. draw a sketch of what a cross section of earth would look like. use a scaling factor of 500 km to 1 cm (i. e., 50,000,000: 1). clearly draw the boundaries between earth's layers, indicate the boundary depth in km, and clearly label each layer. (5 points) a. make a separate sketch of the upper 100 km to show detail. expand the resolution of your sketch to 10 km in 1 cm (1,000,000: 1). clearly label the layers, depths, and boundaries. (4 points) b. how much greater is the resolving power of the second sketch compared to the first sketch? (1 point) extra credit: some of the nuances of plate tectonics do not make sense until you recognize the importance of isostasy. to understand this concept, consider an ice cube that is 10 cm on a side and with a density of 0.9 g cm floating in water with a density of 1.0 g cm. based on your understanding of isostasy, explain why 10% of the ice cube will float above the surface of the water. (5 points)