1. LIVING WITH TECTONIC HAZARDS
What is a natural hazard?
Internal structure of the Earth

2. Death Valley, California, USA

3. Chief Mountain, Montana, USA

4. Great Rift Valley, Madagascar

5. San Andreas Fault, California, USA

6. Cleveland Volcano, Alaska

7. Chaiten Volcano, Chile

8. BY THE END OF THE LESSON
Lets be able to
1. Describe the distribution of different types
of natural hazards.
2. Compare the different types of natural
hazards.
3. Describe the internal structure of the Earth.

9. QUESTIONS
1. What is a natural hazard?
2. What are the kinds of natural hazards?

10. NATURAL HAZARD
• A naturally occurring event that threatens
human lives and causes damage to property.
• Some examples of natural hazards are
earthquakes, volcanic eruptions, floods and
tropical cyclones.

11. QUESTIONS
1. Describe the distribution of different types
of natural hazards. [4]

12. NATURAL HAZARDS

13. DISTRIBUTION
• Where are tectonic hazards located? [2]
• Where are climate-related hazards located?
[2]

14. DISTRIBUTION
• Tectonic hazards such as volcanic eruptions are
mainly concentrated along the coastlines of the
Pacific Ocean,
• with earthquakes lined along the boundaries of
tectonic plates.
• Climate-related hazards such as tropical cyclones
are found between 8° and 15° north and south of
the Equator,
• while droughts and floods are widely distributed
between the Arctic Circle and Antarctic Circle.

15. STRUCTURE OF THE EARTH

16. STRUCTURE OF THE EARTH
• Crust
– Outermost layer of
the Earth
– Consists of solid
rocks such as basalt
and granite
– Continental crust is
less dense than
oceanic crust
– Thickness ranges
from 5km to 70 km

17. STRUCTURE OF THE EARTH
• Mantle
– Consist of upper
mantle of molten
rock called magma
and lower mantle of
solid rock
– Around 2900km
thick
– Temperature between
800°C to 3000°C

18. STRUCTURE OF THE EARTH
• Core
– Made of mostly iron
and nickel
– Molten outer core of
around 2100km thick
– Solid inner core of
around 1200km thick
– Temperature between
3000°C to 5000°C

19. LIVING WITH TECTONIC HAZARDS
Why do plates move?

20. BY THE END OF THE LESSON
Let’s be able to
1. Explain why plates move.

21. TECTONIC PLATES
• The broken up pieces of the Earth’s crust that
move in relation to one another.
• Tectonic plates can be made up of either
continental crust, oceanic crust or a
combination of both.

22. WHY DO PLATES MOVE?
• Convection currents
• Slab-pull force

23. WHY DO PLATES MOVE?

24. WHY DO PLATES MOVE?
• Convection currents
– Magma in the mantle is heated by the core,
causing it to expand, rise and spread out
beneath the plates which cause plates to move
away from each other.
– As the magma nears the Earth’s surface, it
cools, contracts and sinks, bringing plates
towards each other.
– The sinking material heats up again as it nears
the core and the whole process repeats.

25. WHY DO PLATES MOVE?
• Slab-pull force
– Slab-pull force occurs when a denser oceanic
plate subducts below a less dense continental
plate or an oceanic plate.
– As the plate subducts, it pulls the rest of the
plate along, contributing to the downward
movement of convection currents.
– The magma away from the subduction zone
rises thereby contributing to the upward
movement of convection currents.

26. LIVING WITH TECTONIC HAZARDS
Plate movements and resultant
landforms

27. PLATE MOVEMENTS
AND BOUNDARIES
By the end of the lesson, you will be able to,
1. Describe the global distribution of tectonic
plates and types of plate boundaries.
2. Describe the different types of plate
movement.
3. Explain the formation of landforms as a
result of divergent plate movement.

28. PLATES AND PLATE BOUNDARIES

29. DISTRIBUTION
• Seven major plates: African Plate, Antarctic
Plate, Australian Plate, Eurasian Plate, North
American Plate, South American Plate,
Pacific Plate.
• Some minor plates: Arabian Plate, Caribbean
Plate, Cocos Plate, Nazca Plate, Philippines
Plate, Scotia Plate.
• Plates converge, diverge or grind past each
other.

30. PLATE BOUNDARIES
• Divergent
– Plates move away from each other
• Convergent
– Plates move towards each other
• Transform
– Plates move past each other

31. DIVERGENT PLATE BOUNDARIES
• Areas where two plates diverges or move away
from each other due to tensional force,
causing magma to move upward to the
surface where it cools to form new crust.

32. SEA FLOOR SPREADING

33. OCEANIC-OCEANIC PLATE DIVERGENCE
• Fractures and cracks develop along plate
boundaries as two oceanic plates move apart.
• Magma rises from the mantle and escapes
through the cracks to the surface which cools
and solidify to form new sea floor.
• Older crusts are pushed further apart as the
new sea floor forms in a process known as
sea-floor spreading.

35. MID-OCEANIC RIDGE

36. MID-OCEANIC RIDGE
• When two oceanic plates diverges, fractures and
cracks are formed at the plate boundary.
• Magma escapes from the mantle through the cracks
to the surface and solidifies to form new sea floor.
• As more magma solidifies and piles up, a chain of
mountains or undersea ridges is formed on either
side of the spreading zone, forming oceanic ridges.
• An example is the Mid-Atlantic Ridge in the middle
of the Atlantic Ocean, which was formed when the
North American Plate and the Eurasian Plate moved
away from each other.

37. VOLCANIC ISLANDS
• As the magma escapes from various points
along the ridge, cools and builds up above sea
level, volcanic islands are formed.
• An example is the Azores, a series of nine
volcanic islands situated in the North Atlantic
Ocean.

38. Azores Islands, Portugal

39. CONTINENTAL-CONTINENTAL
PLATE DIVERGENCE
• When two continental plates diverge or move
apart, they are stretched, causing fractures to
form at the the plate boundary.

41. RIFT VALLEYS, BLOCK MOUNTAINS
• As two continental
plates diverge, rock
layers are pulled apart
in opposite directions
by tensional force.
• As the two plates
continue to pull apart,
fractures or fault lines
are created at the
boundary, creating a
central mass of rock.

42. RIFT VALLEYS, BLOCK MOUNTAINS
• As the land adjacent to
the central mass
continue to diverge,
the central mass sinks,
forming a linear
depression known as a
rift valley.
• The adjacent sections
which are left standing
are block
mountains.

43. RIFT VALLEYS, BLOCK MOUNTAINS
• As two continental
plates diverge, rock
layers are pulled apart
in opposite directions
by tensional force.
• As the two plates
continue to pull apart,
fractures or fault lines
are created at the
boundary, creating a
central mass of rock.

44. RIFT VALLEYS, BLOCK MOUNTAINS
• As the land adjacent to the central mass continue to
diverge, they sink, forming a linear depression known
as a rift valley.
• The central mass which is left standing is a block
mountains.

45. RIFT VALLEY, BLOCK MOUNTAINS

46. BY THE END OF THE LESSON
Lets be able to
1. Describe the process of subduction.
2. Explain the formation of landforms as a
result of convergence plate movement.

47. CONVERGENT PLATE BOUNDARIES
• Areas where plates converges or move towards
each other due to compressional force,
causing land to subduct or fold.

48. OCEANIC-OCEANIC PLATE
CONVERGENCE
• When two oceanic plates converge, or
when an oceanic plate converges with a
continental plate, the denser plate subducts
under the less dense plate. The area where
this happens is known as the subduction
zone.

49. SUBDUCTION
• Refers to the sideways and downward
movement of the edge of a plate of the earth's
crust into the mantle beneath another plate.
• When denser plate collides with a less dense
plate, the denser plate is subducted (pushed
down) into the molten upper mantle, and
destroyed.

50. SUBDUCTION

51. SUBDUCTION

52. OCEANIC TRENCH
• As two oceanic plates collide, the denser
oceanic plate is forced under/subducted
under the less dense oceanic plate to form a
long, deep and narrow depression known as
an oceanic trench.
• An example is the Mariana Trench formed by
the Pacific Plate subducting under the
Philippines Plate.

53. VOLCANIC ISLAND
• The crust of the subducted oceanic plate
melts and forms magma.
• As the magma escapes through the crust,
volcanoes and eventually a chain or arc of
volcanic islands is formed.
• An example is the Mariana Islands.

54. CONTINENTAL-CONTINENTAL PLATE
CONVERGENCE
• When two continental plates converge, layers
of rock are compressed, leading to folding.

55. FOLDING
• Folding refers to the geologic process of bending or
curving of a stack of originally flat planar surface by
compressional processes along plate boundaries.
• Folding generally occurs in areas with sedimentary
rocks which are softer and more flexible.
• Folding normally does not lead to earthquakes as
stress is released during the process of folding.

56. FOLD MOUNTAINS

57. FOLD MOUNTAINS
• Sedimentary rocks, that make up part of the
Earth's crust are softer and more flexible.

58. FOLD MOUNTAINS
• As two plates collide, compressional forces put
sedimentary rock layers under great pressure,
causing them to bend or fold.

59. FOLD MOUNTAINS
• As the process continues over time, the folded
sedimentary rock layers rise up to great
heights, forming fold mountains.

60. FOLD MOUNTAINS
• The upfold is called the anticline.
• The downfold is called the syncline.

61. OCEANIC-CONTINENTAL PLATE
CONVERGENCE
• When an oceanic plate converges with a
continental plate, the denser plate subducts
under the less dense plate leading to
subduction and folding.

62. SUBDUCTION

63. SUBDUCTION

64. OCEANIC TRENCH
• As an oceanic plate
collide with an
continental plate,
• the denser oceanic
plate is forced
under/subducted
under the less dense
continental plate to
form a long, deep
and narrow
depression known as
an oceanic trench.

65. FOLD MOUNTAINS
• The convergence may cause plate to buckle
and fold, forming fold mountains.
• At the subduction zone, the crust is destroyed
to form magma.
• The magma may escape through cracks and
fractures on the crust, giving rise to
volcanoes.

66. TRANSFORM PLATE MOVEMENT
• Areas where two plates grinds laterally past each
other.
• No land is destroyed or formed but sudden release of
build-up pressure gives rise to powerful earthquakes.

67. TRANSFORM PLATE MOVEMENT

68. Tear Fault /Strike Slip Fault

69. TRANSFORM PLATE BOUNDARY
• Transform plate movement creates
tremendous stress which builds up and when
released, results in violent earthquakes.

70. BY THE END OF THE LESSON
Lets be able to
1. Describe the distribution of volcanoes
around the world.
2. Explain how a volcano is formed.
3. Describe the internal structure of a volcano.
4. Compare the difference between a shield
volcano and a strato volcano.

71. VOLCANOES
• A conical mountain or hill, having a crater or
vent through which lava, rock fragments, hot
vapor, and gas are being or have been erupted
from the earth's crust.

72. DISTRIBUTION

73. DISTRIBUTION
• Volcanoes are located along convergent and
divergent plate boundaries around the world.
• A large number of volcanoes are found around
the edges of the Pacific Ring of Fire, which is
found along the boundaries of converging plates
such as the Pacific Plate and Philippines Plate.
• Volcanoes are also found along diverging plate
boundaries such as in the Atlantic Ocean where
the African Plate and the South American Plate
diverge.

74. FORMATION
• Cracks and fractures are formed as a result of
convergent or divergent plate movements.
• Magma escaped through the cracks and
fractures onto the Earth’s surface as lava.
• As the lava cools and solidifies and builds up
around the vent, conical mountain or hill is
formed which is known as a volcano.

76. STRUCTURE

77. SHAPES AND SIZES
• Volcanoes differ in shapes and sizes due to
the difference in viscosity, which refers to the
stickiness of the lava, which is in turn
determined by the amount of silica in the
lava.

78. SHAPES AND SIZES
• Low-silica lava or less viscous lava flows more
easily, and allows gases to escape easily.
• High-silica lava or more viscous lava flows
less readily, and traps gases more easily.

79. SHIELD VOLCANOES
• Gently sloping
• Broad submit and base
• Formed by lava low in viscosity (low-silica
lava)
• Lava spreads over a large area
• Lava cools and solidifies slowly
• Lava traps less gas
• Less violent eruption

80. Mauna Loa Volcano, Hawaii

81. SHIELD VOLCANOES

82. STRATO VOLCANOES
• Steep slopes at the top
• Gentle slopes towards the bottom
– Small and light materials are be deposited further
away
• Formed by lava high in viscosity (high-silica
lava)
• Lava spreads over a small area and solidifies
quickly
• Traps gas
• Erupts violently

83. Mount Mayon, Philippines

84. Mount Vesuvius, Italy

85. STRATO VOLCANOES

86. Mount Vesuvius, Italy

87. CALDERA
• The summit of a volcano may be blown off
during an explosive eruption.
• The sides of the crater collapse inwards due to
the loss of structural support.
• As a result, a large depression known as a
caldera is formed.

88. LIVING WITH TECTONIC HAZARDS
Phenomena found at plate boundaries

89. BY THE END OF THE LESSON
Let’s be able to
1. Describe an earthquake.
2. Describe the focus and epicentre of an
earthquake.
3. Describe the factors influencing the impact
of earthquakes.

90. EARTHQUAKES
• A vibration in the Earth’s crust caused by the
sudden release of stored energy in the rocks
along fault lines.

91. EARTHQUAKES
• Earthquakes occur when there is plate
movement along plate boundaries.
• The plate movements cause the slow build-up
of stress on the rocks found on either side of
the fault.
• When the rocks can no longer withstand the
stress, a slip which can span many metres
occur, causing an earthquake.

92. FOCUS, EPICENTRE
• The focus of an earthquake refers to the
point of origin of the seismic waves released
when an earthquake occurs.
• The point on the Earth’s surface directly
above the focus is the epicentre.

94. FACTORS INFLUENCING THE
IMPACT OF EARTHQUAKES.
1. Population density
2. Level of preparedness
3. Distance from the epicentre
4. Time of occurrence
5. Type of soil

95. POPULATION DENSITY
• Earthquakes are more likely to result in more
casualties and damages in areas with high
population density due to the presence of
more people and properties.

96. LEVEL OF PREPAREDNESS
• Earthquakes are less likely to result in a lot of
damages when there is a high level of
preparedness such as the availability of
evacuation plans, trained rescue workers and
rescue action plans.

97. DISTANCE FROM THE EPICENTRE
• Earthquakes are more likely to result in more
casualties and damages when the area is
closer to the epicentre as the strength of
seismic waves is strongest at the epicentre.

98. TIME OF OCCURRENCE
• Earthquakes are more likely to result in more
casualties and damages when it happens at
night when most people are sleeping, as there
is a higher chance of being trapped in houses
due to shorter reaction time to evacuate.

99. TYPE OF SOIL
• Earthquakes are more likely to result in more
casualties and damages when it happens in
places where sediments are loose and
unconsolidated as the seismic waves are
amplified in these areas.

100. BY THE END OF THE LESSON
Let’s be able to
1. Explain how tsunamis are formed by seismic
activity.
2. Describe hazards associated with
earthquakes.

101. HAZARDS ASSOCIATED
WITH EARTHQUAKES
• Tsunamis
• Disruption of services
• Fire
• Landslides
• Destruction of properties
• Destruction of infrastructure
• Loss of lives

102. TSUNAMIS
• Refers to an unusually large sea wave which
can be formed by,
– A large offshore earthquake.
– An explosive underwater volcanic eruption.
– An underwater landslide.
– A landslide above sea level which causes
materials to plunge into the water.

103. FORMATION OF TSUNAMIS
• Seismic energy from an offshore earthquake
forces out a mass of water, generating large
waves.
• The waves may begin at a height of 1 metre with
wave lengths of 100km and speeds of around
800km/h.
• On reaching shallow water, greater friction slows
the waves down and forces an increase in wave
height.
• As the waves reached the shore, the waves could
be travelling at 50km/h and reach heights of
around 15m, forming a tsunami.

104. FORMATION OF TSUNAMIS

105. Japan earthquake, 2011

106. DISRUPTION OF SERVICES
• Earthquakes can disrupt services such as the
supply of electricity, gas and water and
potentially affect a large area.
• For example, the earthquake in Kobe, Japan,
in 2004 damaged pipes and transmission
lines, leading to disrupted electricity and
water services for about 1 million people.

107. FIRE
• Earthquakes may expose electrical cables
which may ignite flammable items such as
chemicals and leaked gas from ruptured gas
pipes.
• For example, the earthquake in Kobe, Japan,
in 1995 caused extensive fires as a result of
toppled gas cookers and kerosene stoves from
households preparing their morning meals.

108. Japan earthquake, 2011

109. LANDSLIDES
• Earthquakes may cause landslides, which
refer to the rapid downslope movements of
soil and rock due to the the weakening of the
slopes of hills and mountains, and can bury
people and infrastructure in seconds.
• For example, a massive landslide was
triggered by an earthquake in Peru in 1970,
which lead to a death toll of 18,000.

110. DESTRUCTION OF PROPERTIES
• Earthquakes may lead to the destruction of
properties as homes may be destroyed,
causing people to lose their homes overnight.
• For example, the tsunami in 2011 travelled
more than 10km inland into Japan, destroying
many homes in the process, leading to a
severe shortage of homes.

111. Sichuan earthquake, 2008

112. DESTRUCTION OF INFRASTRUCTURE
• Earthquakes may cause cracks to form in
infrastructure such as roads and bridges
hence disrupting transport and rescue
services.
• For example, many places became
inaccessible after the earthquake in Kobe,
Japan, in 1995 due to the destruction of roads.

113. Haiti earthquake, 2010

114. LOSS OF LIVES
• Earthquakes and their associated hazards
such as landslides and tsunamis often lead to
the loss of lives of people living in earthquake
zones.
• For example, 28,000 lives are estimated to
have been lost in the Tohoku, Japan
earthquake in 2011.

116. BY THE END OF THE LESSON
Let’s be able to
1. Describe the difference between active,
dormant and extinct volcanoes.
2. Describe the risks of living near volcanic
areas.
3. Describe the benefit of living near volcanic
areas

117. ACTIVE, DORMANT, EXTINCT
• Active volcanoes refer to volcanoes which are
currently erupting or are expected to erupt in
the near future.
• Dormant volcanoes are currently inactive but
may erupt in the near future.
• Extinct volcanoes refer to volcanoes without
seismic activity and with no evidence of
eruptions for the past thousand of years.

118. RISKS OF LIVING NEAR
VOLCANIC AREAS
1. Destruction by volcanic materials
2. Landslides
3. Pollution
4. Effects on weather

119. DESTRUCTION BY
VOLCANIC MATERIALS
• Volcanic eruptions can result in pyroclastic
flows which is a fast-moving current of hot
gas and rock that can reach speeds of to 700
km/h and 1,000 °C, capable of destroying
everything in its path.
• For example, Mount Merapi, Indonesia has
been known for violent eruptions that are
accompanied by pyroclastic flows.

122. LANDSLIDES
• Landslides can occur due to the collapse of a
volcanic cone during a volcanic eruption and
have the potential to obstruct flow of rivers
thereby causing floods, block roads or bury
entire villages.
• For example, the 1985 eruption of Nevado del
Ruiz in the Andes mountains triggered a
landslide that killed more than 20,000
people.

123. POLLUTION
• Volcanic eruptions can release gases such as
carbon dioxide, sulphur dioxide and carbon
monoxide which is harmful to people when
inhaled in large quantity.

124. EFFECTS ON WEATHER
• Ash particles ejected during volcanic
eruptions may reflect the Sun’s energy back
into space, leading to global cooling ranging
from a few months to years.
• For example, the 1815 eruption of Mount
Tanbora in Indonesia reduced global
temperatures by 1.7°C.

125. BENEFITS OF LIVING NEAR
VOLCANIC AREAS
1. Fertile volcanic soil
2. Precious stones and minerals, building
materials
3. Tourism
4. Geothermal energy

126. FERTILE SOIL
• Lava and ash from volcanic eruptions break
down to form fertile soils which are favorable
to agriculture.
• For example, the volcanic soils of Java and
Bali in Indonesia produces very bountiful
harvests of crops such as tea and coffee each
year.

127. PRECIOUS STONES AND MINERALS,
BUILDING MATERIALS
• Volcanic rocks can be rich in precious stones
such as diamonds and materials such as
sulphur which can be extracted when the
upper layers of volcanic rocks are eroded.
• For example, the old volcanic rocks at
Kimberly, South Africa contain one of the
world’s richest source of diamonds.

128. TOURISM
• Volcanic areas are popular tourist attractions
as they offer a variety of activities such as
hiking, camping or just enjoying the scenery.
• For example, Mount Fuji, Japan is a very
popular tourist destination and has been
drawing millions of tourists each year.

129. GEOTHERMAL ENERGY
• Volcanoes are sources of geothermal energy,
which refers to energy derived from heat in
the earth’s crust.
• For example, most of Iceland’s electricity is
generated from geothermal power because of
the large number of volcanoes in the country.

130. BY THE END OF THE LESSON
Let’s be able to
1. Describe the various approaches to
responding to earthquakes.
2. Evaluate the effectiveness of preparedness
measures in response to earthquakes.

131. APPROACHES
• Fatalistic approach
– Accepts that earthquakes are unavoidable and
– May resist evacuation when earthquake happens
• Acceptance approach
– Accepts the risks of living earthquakes
• Adaptation approach
– Accepts the risks of living earthquakes and
emphasizes well-preparedness to earthquakes.

132. PREPAREDNESS MEASURES
• Land use regulations
• Building design
• Infrastructure development
• Emergency drills
• Use of technology

133. QUESTION
• Evaluate the effectiveness of earthquake
preparedness measures. [8]

134. LAND USE REGULATIONS
Land use regulations refers to a set of rules implemented m
earthquake zones to restrict development in certain areas.
For example, in California, United States of America, all new
building developments are not built across fault lines or areas
at risk of liquefaction. Although land use regulations have
been effective in mitigating the impact of earthquakes, they
are very costly to implement. This is because these
regulations are often carried out in already built-up areas that
require the government to repurpose the land or purchase
from private owners first before repurposing. As such,
although land use regulations is an effective measure, it is
not a measure that can be implemented by earth-quake
prone countries with little resources such as Haiti.

135. BUILDING DESIGN
• Building design refers to constructing buildings
with effective design that can reduce the collapse
of buildings during earthquakes. For example,
the Taipei 101 building, Taiwan, was built with
steel and reinforced concrete and sits on a wide
and heavy base. This has allowed the skyscraper
to withstand earthquakes successfully. However,
constructing buildings with such designs are
expensive and requires highly skilled labour,
hence this strategy is not a available to poor
countries that are earthquake prone.

136. INFRASTRUCTURE DEVELOPMENT
Infrastructure development refers to building
infrastructure with advanced engineering to withstand
the vibration associated with earthquakes. For example,
roads, bridges and dams are built to resist ground
shaking in China and Canada so they do not collapse
during earthquakes. This has been successful in
reducing damages to valuable infrastructure and loss of
lives. However, infrastructure development is very costly
strategy, be it building new ones or converting existing
infrastructure, hence this strategy is not a available to
poor countries that are earthquake prone.

137. EMERGENCY DRILLS
• Emergency drills refers to the frequent practice of
steps to take when an earthquake occurs. This
creates awareness among the population and
prevents widespread panic during an earthquake.
For example, Japan conducts emergency drills
every year during a Disaster Prevention Day, that
involves people all over Japan in an earthquake
stimulation exercise. However, emergency drills
may lose its effectiveness as people may become
complacent overtime, especially when the last
earthquake happened a long time ago.

138. USE OF TECHNOLOGY

139. BY THE END OF THE LESSON
Let’s be able to
1. Evaluate the effectiveness of short-term and
long-term responses to earthquakes.

140. SHORT-TERM RESPONSES
• Short-term responses are those that occur
immediately and last for weeks after the
occurrence of an earthquake.
1. Handling the status of the affected area
2. Searching for and rescuing casualties
3. Providing medical aid, food and water
4. Setting up emergency shelters
5. Calling for humanitarian aid

141. HANDLING THE STATUS
OF THE AFFECTED AREA

142. SEARCHING FOR AND
RESCUING CAUSALITIES

143. PROVIDING MEDICAL AID,
FOOD AND WATER

144. SETTING UP EMERGENCY SHELTERS

145. CALLING FOR
HUMANITARIAN AID

146. LONG-TERM RESPONSES
• Long-term responses can stretch over months
and years and involve rebuilding an affected
region.
1. Improving infrastructure
2. Compensating people who lose their land
and property
3. Ensuring the affected region recovers
economically
4. Improving health options

147. IMPROVING INFRASTRUCTURE

148. COMPENSATING PEOPLE WHO LOSE
THEIR LAND AND PROPERTY

149. ENSURING THE AFFECTED REGION
RECOVERS ECONOMICALLY

150. IMPROVING HEALTH OPTIONS

151. QUESTION
• “Long-term responses to earthquakes are
more effective than short-term responses.”
How far do you agree with this statement?
[8]

152. END