3. Who was the first person to describe the core?
A. Inge Lehmann
C. Andrija Mohorovicic
B. Beno Gutenberg
D. Richard Dixon Oldham

4. Which refer to the depths at which the core layer starts and ends respectively? A. 2300 and 4000 km
C. 2800 and 4271 km
B. 2600 and 5771 km
D. 2900 and 6371 km

5. Which of the following is true about the inner core?
A. It is believed to be a liquid body.
C. It is believed to be a gaseous body.
B. It is believed to be a solid body.
D. It is believed to be a semi solid body.

6. Which of the layers does NOT transmit the S-waves?
A. crust
B. mantle
C. inner core
D. outer core

7. What is the density of the Earth's center?
A. 8.8 g/cc
B. 9.9 g/cc
C. 13 g/cc
D. 12.7 g/cc

8. What do you call the layer which is said to support the slow-moving tectonic plates?
A. core layer
B. lithosphere
C. asthenosphere
D. Mohorovicic sphere

9. What is the thickness of the inner core?
A. 1790 km
B. 2890 km
C. 3790 km
D. 4790 km

10. What is the layer which is believed to be the source of volcanic activity?
A. Inner core
B. Outer Core
C. Asthenosphere
D. Mohorovicic layer

11. Which layer of the Earth is the densest?
A. crust
B. mantle
C. outer core
D. inner core

12. How does density affect the organization of the Earth's interior? The densest material is
A. near the equator
C. closest to the mantle
B. closest to the center
D. farthest from the centel

13. What conclusion can be made about the density of the rigid crust that floats on the hot, plastic material of the mantle? The crust
A. is denser and it sinks
C. is less dense and it floats.
B. is denser and it floats.
D. has the same density as the mantie.

14. Which rocks should be labeled as "core" rocks?
A. limestone and salt
C. basalt and granite
B. iron and nickel
D. aluminum and silicate

15. How do you compare the densities of the Earth's crust, mantle, and core? The mantle is
A. denser than both the core and the crusi.
B. less dense than both the core and the crust.
C. denser than the core but less dense than the crust
D. less dense than the core but denser than the crust​