Layers of the Earth and its Composition

Question 1

1) Which of the following separates the upper mantle from the lower mantle?
a) Mohorovičić discontinuity
b) Repetti discontinuity

Answer 1

B. Repetti discontinuity separates the upper mantle from the lower mantle

Question 2

2) Which of the following explains why the asthenosphere flows like a very viscous fluid?
a) Temperature and pressure in the asthenosphere are high enough that rocks become ductile
and deform easily.
b) There is high pressure and extremely low temperature in the asthenosphere that deforms the
rocks.

Answer 2

A. High temperature and pressure make the rocks ductile and deform them easily.
For this reason, the asthenosphere flows like a very viscous fluid (but not liquid) and moves
independently from the overlying lithosphere.

Question 3

3) What do you call the dominant rock type located in the mesosphere?
a) perovskite
b) gneiss

Answer 3

A. Perovskite is the dominant rock type in the Mesosphere.

Question 4

4) Which of the following is TRUE about the Earth’s Crust?
a) The oceanic crust is thinner than the continental crust
b) Crust is the thickest layer of the Earth.

Answer 4

A. The oceanic crust has an average thickness of about 7 km which is thinner than
the continental crust.

Question 5

5) Which of the following layers of the Earth is made out of liquid?
a) outer core
b) inner core

Answer 5

A. The outer core is the only layer of the Earth that is made out of the liquid. This is due
to the extremely high temperature in this layer of about 3000°C

Question 6

6) The lithosphere, from the Greek word lithos meaning “stone”
a) True
b) False

Answer 6

A. True

Question 7

7) There are two types of crust– the continental crust and the oceanic crust.
a) False
b) True

Answer 7

B. True

Question 8

8) The boundary between the crust and mantle is called the _____ discontinuity, which is marked by a change in chemical composition.
a) Gutenberg
b) Mohorovičić

Answer 8

B. Mohorovičić

Question 9

9) The core begins at the mantle-core boundary, the _____ discontinuity, located at the 2,900 km depth.
a) Gutenberg
b) Mohorovičić

Answer 9

A. Gutenberg

Question 10

10) The asthenosphere (from the Greek word asthenēs meaning “weak”)
a) False
b) True

Answer 10

B. True