6. Which is made up of the liquid part of the mantle and the outer core? A. Outer core B. Inner core C. Lithosphere D. Asthenosphere 7. Which materials make up the liquid part of the mantle? whe A. Liquid gases C. Molten rocks B. Molten plastics D. Liquid iron and nickel 8. Why are rocks in the lower mantle molten? vo A. Because of gravity C. Because of too much air B. Because of high temperature D. Because water is mixed with it 9. Which causes the sudden breaking of rocks in faults or cracks in the crust? A. Very heavy rains B. Strong thunderstorm C. Overpopulation in an area D. Movement of molten rocks 10. Which natural phenomenon occurs when rocks break in faults or cracks in the crust due to movement of molten material? A. Tornado B. Landslide C. Earthquake D. Volcanic eruption.