Chapter IV

Question 1

earth’s center, where pressures and temperatures are very high

Answer 1

core

Question 2

the section of earth’s interior that lies above the outer core and has the most mass

Answer 2

mantle

Question 3

liquid rock within earth

Answer 3

magma

Question 4

the theory that earth’s crust is divided into rigid plates that slowly move across the upper mantle

Answer 4

plate tectonics

Question 5

the process by which earth’s plates slowly move across the upper mantle

Answer 5

continental drift

Question 6

places on earth’s surface where the crust stretches until it breaks

Answer 6

rift valleys

Question 7

areas of the ocean floor where rocks gradually sink, because they have no supporting heat below them; the world’s flattest and smoothest regions

Answer 7

abyssal plains

Question 8

areas where continental surfaces extend under the shallow ocean water around the continents

Answer 8

continental shelves

Question 9

a deep valley marking a collision of plates, where one plate slides under another

Answer 9

trench

Question 10

places where rocks have been compressed into bends by colliding plates

Answer 10

folds

Question 11

places where rock masses have been broken apart and are moving away from each other

Answer 11

faults

Question 12

the process by which rocks break and decay over time

Answer 12

weathering

Question 13

small particles if weathered rock

Answer 13

sediment

Question 14

process of removing salt from ocean water

Answer 14

desalinization

Question 15

movement of water through the hydrosphere

Answer 15

hydrologic cycle

Question 16

first and smallest streams formed form the runoff of a mountain, eventually forming rivers

Answer 16

headwaters

Question 17

any smaller stream or river that flows into a larger stream or river

Answer 17

tributary

Question 18

the entire region drained by a river and its tributaries

Answer 18

watershed

Question 19

a region drained by a river and its tributaries

Answer 19

drainage basin

Question 20

semi-enclosed bodies of water, seawater, and freshwater formed where a river meets an inlet of the sea

Answer 20

estuaries

Question 21

landscapes that are covered with water for at least part of the year

Answer 21

wetlands

Question 22

broken down plant and animal matter in soil

Answer 22

humus

Question 23

downward movement of minerals and humus in soils

Answer 23

leaching

Question 24

plowing fields across a hill, rather than up or down the hill

Answer 24

contour plowing

Question 25

a condition in which soil has lost nutrients and becomes nearly useless for farming

Answer 25

soil exhaustion

Question 26

the practice of planting different crops in a field in alternating years

Answer 26

crop rotation

Question 27

a process in which water is artificially supplied to the land

Answer 27

irrigation

Question 28

salt buildups in the soil

Answer 28

soil salinization

Question 29

destruction or loss of forests

Answer 29

deforestation

Question 30

the replanting of a forest

Answer 30

reforestation

Question 31

artificial channels for transporting water

Answer 31

aqueducts

Question 32

rock layers where groundwater is plentiful

Answer 32

aquifers

Question 33

groundwater that is not replenished by rain

Answer 33

fossil fuels