Chapter 31

Question 0

Asthenosphere

Answer 0

the upper layer of the earth’s mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.

Question 1

Lithosphere

Answer 1

the rigid outer part of the earth, consisting of the crust and upper mantle.

Question 2

Lower mantle

Answer 2

the deeper part of the mantle

Question 3

Outer core

Answer 3

The outer core of the Earth is a liquid layer about 2,266 km thick composed of iron and nickel which lies above the Earth’s solid inner core and below its mantle.

Question 4

Inner core

Answer 4

The inner core of the Earth, its innermost part, is a primarily solid ball with a radius of about 1,220 km, according to seismological studies. It is believed to consist primarily of an iron–nickel alloy, and to be about the same temperature as the surface of the Sun: approximately 5700 K.

Question 5

Continental drift

Answer 5

gradual movement of the continents across the earth’s surface through geological time.