30. Materials in the mantle flow up and down. Which of the following best describes the mantle? A. a solid layer B. partially liquid C. a metallic layer D. very hot layer 31. Which of the following happens when plates diverge or move away from each other? A. The crust is destroyed. B. New crust is produced because magma rises, then cools off and turns into solid. C. Earth's size changes because mountains are added on the earth's surface. D. The mantle rises. 32. The word used to refer to the shaking of the ground due to any activity in the lithosphere. A. intensity B. earthquake C. Volcanism D. wave 33. Where is the source of heat in a mantle convection current? A. the Sun B. the crust C. the core D. the moon 34. Which of the following is NOT a driving force of tectonic plates? A. ridge push B. slab push C. drag force D. mantle convection 35. It is a measure of how much mass there is in a volume of a substance. A. volume B. temperature C. density D. mass 36. The plastic-like upper portion of the mantle is called. A. the magma B. the core C. the lithosphere​