Study the images of earth’s crust and mantle in two different areas. how is item a different from item b? the crust under the ocean in item a is thicker than the crust under the mountain in item b. the mantle under the ocean in item a is thinner than the mantle under the mountain in item b. the crust in item a is found partially below sea level as compared to the crust in item b. the mantle in item a is located far below a mountain as compared to the mantle in item b.