Which part of the mantle is made off soft rock? lithosphere asthenosphere outer core lower mantel

Mostly Iron and some small amounts of nickel, sulfur and oxygen. The "weak sphere" - is the soft layer of the mantle where pieces of the lithosphere move. It is made of solid rock that flows like putty. Beneath the asthenosphere, the strong lower part of the mantle is the "middle sphere

Under pressure

Fish living closer to the surface of the ocean may have a swim bladder – that's a large organ with air in it, which helps them float up or sink down in the water. Deep sea fish don't have these air sacs in their bodies, which means they don't get crushed.