On the basis of the data presented below in the table, estimate the fractions of Earth's volume represented by (a) the inner core, (b) the outer core. (c) the mantle, and (d) the crust. r is the inner and r2 is the outer radius of the Earth's layers. (6 marks). Layer Crust Mantle Outer Core Inner Core 6348 3488 1278 P. 6378 6348 3488 1278