radio communication is possible around the curvature of the Earth because of the
A ozone layer
B troposphere
C stratosphere
D ionosphere
among the effects of plate tectonics on the Earth are
A rivers
B rain
C cooling
D mountains
the Earth and moon are both about the same distance from the sun, yet the Earth (on the average) is much warmer than the moon. why?
A the moon is smaller than the Earth
B the moon's night is longer than the Earth's
C the moon has almost no atmosphere compared with the Earth
D the surface of the moon is, on the average, darker than the surface of the Earth
the major constituents of the Earth's atmosphere are
A 95% carbon dioxide, some water vapor
B 77% nitrogen, 21% oxygen
C 77% oxygen, 21% nitrogen
D methane, ammonia, water vapor and carbon dioxide in about equal amounts
the insulating effect of the Earth's atmosphere is called:
A the coriolis effect.
B radiation blanketing.
C ozone infiltration.
D the greenhouse effect.
which of the following is true?
A transverse waves are not transmitted by a liquid but are absorbed.
B compressional waves are not transmitted by a liquid but are absorbed.
C transverse and compressional waves are absorbed by a liquid.
D transverse and compressional waves are transmitted by a liquid.
continental drift on the Earth is now thought to be caused by
A the steady flow of atmospheric winds in the atmosphere at lower altitudes
B precession and nutation of the Earth's spin axis
C circulation currents in the deep interior, causing slabs of the Earth's crust to move slowly
D the forces of ocean tidal effects on the continental shelves around the land masses
how do we know that the Earth has differentiated?
A the crust density is lower than the mean density.
B presence of a magnetic field.
C presence of nitrogen in the atmosphere
D (a) and (b).
E (a) and (c).
of those terrestrial planets having atmospheres, which planet's atmosphere is not primarily carbon dioxide?
A Mercury
B Venus
C Earth
D Mars
what is believed to be the source of water in the Earth's oceans?
A melted polar ice
B primordial glaciers
C impacts of comets from space
D volcanic out gassing of water vapor
a magnetic dynamo is caused by a combination of convection in a molten cor and
A rotation
B cosmic rays from space
C lunar tidal action
D the solar gravitational pull on the Earth's equatorial bulge
continental drift may be caused by
A strong winds.
B Earthquakes.
C convection in the upper mantle.
D volcanoes.
chemical differentiation of the Earth
A has not occurred -- the Earth is chemically homogeneous
B occurred in the era about 4 to 4.5 billion years ago when the Earth was mo
C occurred only since homo sapiens has been around
D was caused by the spin of the Earth, which concentrated the heavy elements like iron at
the equator
the Earth's structure is differentiated. this means that the least dense materials make up the ______ , and the most dense the ______.
A core, mantle.
B core, crust.
C mantle, crust.
D crust, mantle.
E crust, core.
large quantities of new lava rock are emerging from the mantle to form new portions of the crust. where does this occur?
A along the tops of major continental mountain ranges
B along the continental shelf adjacent to the continents
C along the major continental river basins where the crust is thinnest
D along the length of the submarine ridges in the middle of the major oceans
winter in the northern hemisphere occurs when
A sunlight falls most obliquely upon that region of Earth
B the Earth's axis is at its largest angle with respect to the ecliptic plan because of precession
C the Earth is furthest from the ecliptic plane
D the Earth is furthest from the sun
the Earth has an average density of
A 2 times that of water
B greater than 10 times that of water
C that of water
D 5.5 times that of water
the molecular oxygen in the present Earth's atmosphere was most probably produced
A by primitive life forms, relatively recently in geological time
B from volcanic eruptions as the primitive Earth cooled down
C at the formation of the Earth, and has always been present
D from seawater, by out gassing
pangaea
A existed about 2 million years ago
B is a mid-atlantic mountain range
C was the single super-continent
D was an ancient civilization
it is possible for a solid core to be surrounded by a molten core because
A the passage of s waves through part of the core requires this to be the case
B very high temperatures cause the core elements to decay into different elements with a high melting point
C radioactive decay in the solid core heats the outer core to the melting point
D material under a large pressure has a higher melting point
the Earth's primitive atmosphere
A was primarily hydrogen and helium, like the giant planets'
B was mostly nitrogen, since plants hadn't yet formed to add oxygen
C escaped due to the Earth's rapid loss of heat from its interior
D was absorbed by the Earth's crust to form rocks
the Earth's primitive atmosphere
A was created by the action of marine algae
B resulted from extensive volcanic activity and out gassing
C is what remained after the solar gale blew away the lighter hydrogen-helium atmosphere
D was a prerequisite for the appearance of life
the Earth's primordial atmosphere was most likely
A co2 and h2o
B nh3, ch4, h2 and he
C atomic h and atomic he
D none of the above
what is believed to be the source of water in the Earth's ocean?
A water in rocks in the interior
B water in the atmosphere
C water in the polar caps
D water in primordial glaciers
the average density of the Earth seems to indicate that it has a core that is:
A about like the crust.
B much less dense than the crust.
C more like the density of water and therefore liquid.
D more dense than the crust and probably mostly iron.
we might expect the Earth's core to be more dense than its crust because
A in the early stage of Earth's formation, more dense materials would sink to the center, while less dense materials would float at the surface.
B the density of material in the crust is less than the overall average density of the Earth.
C any material would become more dense as it is compressed by the weight of material above it.
D all of the above.
E only (a) and (b) above.
what is believed to be the source of water in the Earth's ocean?
A water in rock in the interior.
B water in the atmosphere.
C water in the polar caps.
D water in primordial glaciers.
the Earth's shape is most accurately described as a(n)
A sphere
B oblate spheroid
C prolate spheroid
D dodecahedron
the Earth's atmosphere is primarily
A nitrogen
B oxygen
C co2
D h and he
the present atmosphere of the Earth is different from the atmosphere of a few billion years ago in that
A there was no water vapor until the oceans started to evaporate
B there was more ozone then because nobody was using deodorant or hair spray
C oxygen has been added in the last few billion years by the photosynthetic action of green plants
D there was no nitrogen until biological processes began
one required condition for "seasons" to occur on a planet is that
A the planet have its axis perpendicular to its orbital plane
B the planet have a thick atmosphere
C the planet have its spin axis tilted with respect to the perpendicular to its orbital plane
D the planet's distance from the sun vary
the surface temperature of Venus is much higher than expected because
A it rotates very slowly
B its atmosphere is very opaque
C its atmosphere is very transparent
D it is very close to the sun
the method used to estimate the age of the Earth is
A carbon-14 dating of organic materials
B estimating the amount of erosion of mountains
C radioactive dating of rocks using elements with short half-lives
D radioactive dating of rocks using elements with long half-lives
the Earth's magnetosphere arises from the interaction of the Earth's
A charged particles in the solar wind.
B neutral particles in the solar wind.
C charged particles from the moon.
D charged particles from Jupiter.
E none of the above.
which of the following is true about the Earth's magnetic field?
A it helps protect us from the solar wind.
B it is too weak to be of any assistance except in direction finding.
C it is aligned with the Earth's spin axis.
D it is responsible for the solar wind particles.
which of the following is a way for us to learn about our planet's core?
A sounding rockets
B seismic waves
C x-ray probes
D examining sedimentary rocks
the region of the atmosphere in which all weather occurs is called:
A the troposphere.
B the stratosphere.
C the mesosphere.
D the thermosphere.
elements which spontaneously decay into different elements are
A isotopes
B radioactive
C extremely rare
D very common
the age of the Earth is considered to be
A about 4.5 million years
B about 4.5 billion years
C only a few 100,000 years
D about 10 million years
to arrive at an estimate of the Earth's age, we apply the technique of
A carbon-14 dating of organic materials.
B radioactive dating of rocks containing uranium.
C tree-ring dating.
D estimating the amount of salt water in the oceans.
one of the high temperature regions in the upper atmosphere is due to atmospheric absorption by which of the following?
A water vapor.
B ozone.
C helium.
D hydrogen.
the chemical make-up of the central core of the Earth is considered to be
A very close to that at the surface, of silicon-rich rocks and minerals
B mainly solid hydrogen and helium, similar to that of the giant planets
C almost pure iron
D iron-rich minerals
the main driving source of the Earth's evolution is
A life.
B meteoritic bombardment from space.
C outflow of heat from the Earth's interior.
D the influence of the Earth's magnetic field.
E the development of oceans of surface water.
the point on the Earth's surface directly above an Earthquake is known as its
A epicenter
B shadow zone
C discontinuity
D focus
what is the source of the auroras (the northern lights)?
A interaction of the solar wind particles with the Earth's atmosphere.
B heating of the atmosphere by lightning.
C sunlight reflected by dust in the Earth's atmosphere.
D static electricity in the atmosphere when its cold and dry.
the average speed of motion of the plates on the Earth's surface is
A a few centimeters per century
B a few centimeters per year
C about 10 meters per year
D very small, less than a millimeter per century
200 million years ago, the continents
A formed a single super-continent.
B were much like they are today.
C did not exist.
D were totally submerged in water.
which of the following molecular species is vital in the greenhouse effect in planetary atmospheres?
A nitrogen
B ozone
C carbon dioxide
D oxygen
the estimated age of the Earth is based upon
A the discovery of ancient fossil beds
B mathematical calculations dealing with the origin of the solar system
C the degree of salinity of the oceans over the centuries
D studies involving radioactive decays within the crust of the Earth
the study of the motions of the Earth's crustal plates is generally called:
A Earth dynamics.
B crustal slippage.
C terrahydrodynamics.
D plate tectonics.
particles from the sun interact with the Earth's ionosphere to produce
A aurora borealis
B clear radio transmissions
C cosmic rays
D protons and electrons
what do we believe generates the magnetic field of the Earth?
A the presence of solid iron in the core acting like a huge bar magnet
B magnetized rock along mid-ocean ridges
C a dynamo generated by a metallic, liquid core
D the Earth's magnetic field is an extension of that of the sun.
the van allen belts are
A regions on Earth, near the north and south poles, in which auroras are obs
B regions near the Earth's equator where the gravitational field is minimize
C zones containing charged particles surrounding the Earth
D regions in the Earth's mantle where certain minerals occur with high abundance
the principal source of heat to the Earth's atmosphere is
A the heating of the surface by the sun
B volcanism on the Earth
C continental drift
D release of stored heat from the hot core of the Earth
if the half-life of a given isotope is one million years, than one may exp what fraction of the original number of atoms to remain after three million years
A 1/16
B 1/8
C 1/4
D
the fact that the Earth is not a sphere was discovered by
A early explorers
B visual observations of the astronauts
C astronomers measuring stellar positions from different locations on the Earth
D no choice
what is believed to be the source of oxygen in the Earth's atmosphere?
A biological activity such as photosynthesis
B out gassing from the Earth's interior
C ultraviolet breakdown of water vapor
D automobile exhaust
the Earth's atmosphere interferes with astronomical observations because
A some wavelengths are absorbed by the atmosphere.
B weather may make observations impossible.
C it makes stars twinkly.
D all of the above.
E (a) and (b) above.
the Earth's atmosphere helps to keep the surface warm by
A keeping out the cold space.
B absorbing a large fraction of the incoming sunlight.
C absorbing a large fraction of the outgoing infrared.
D reflecting sunlight back to space.
E containing a large fraction of oxygen and nitrogen.
the surface temperature of the Earth is actually warmer than expected from the amount of sunlight received. this is a result of
A the greenhouse effect
B the force of gravity on the Earth's atmosphere
C the Earth's magnetic field
D large outflow of heat from the Earth's interior
the Earth's atmosphere today ______
A remains unchanged from its formation.
B is the result of evolution through a number of phases.
C is the result of current volcanic out gassing.
D is the result of particle deposition by the solar wind.
the Earth's crust is best characterized as ______. this is described by the ______.
A static, minimum energy theory.
B static, steady state theory.
C evolving, plate tectonic theory.
D evolving, greenhouse theory.
according to current theories the center of the Earth's core is:
A molten.
B solid.
C part solid and part liquid.
D no answer here because we don't know anything about the Earth's core.
the mean density of the Earth is 5.5 times that of water while that of the crust is only 3 times that of water. this suggests that:
A the Earth has differentiated.
B the Earth's core has a lower density than the crust.
C the Earth may have an iron core.
D (a) and (c).
E (a) and (b).
the Hawaiian islands experience continuous volcanic activity because
A they happen to be at a focal point for seismic waves from Earthquakes around the pacific ocean
B they are in the center of a major ocean
C they lie right on the boundary between tectonic plates
D they lie directly above a hot-spot plume in the Earth's interior
most of the weather processes in our atmosphere take place at altitudes
A below 10 km
B between 10 and 50 km
C between 50 and 80 km
D below 2 km
the Earth's magnetosphere is
A a layer in the Earth's atmosphere between stratosphere and thermosphere, where motions are governed by magnetic effects
B a cavity in the solar wind, carved out and controlled by the Earth's magnetic field
C the molten core of the Earth, whose motions produce the magnetic field
D a region of the Earth's surface near the magnetic poles
the Himalayas
A are near a subduction zone
B are the result of the breakup of gondwanaland
C are the result of the creation of pangaea
D resulted from the collision between continents
according to the dynamo theory
A the Earth has a lead core.
B the Earth's crust is magnetic.
C the atmosphere is shaped by the magnetic lines of force.
D a partially liquid, spinning core produces the magnetic field.
how does the temperature of the Earth's atmosphere vary with height over the range 0 to 500 km?
A it decreases and increases several times
B it always remains well below the surface temperature
C it rises steadily until it reaches a high and constant value above 200 km
D it remains approximately constant at room temperature over the whole range
how is the Earth's age most precisely determined?
A by studying old river beds.
B by carefully examining of old fossils.
C through radioactive age dating.
D all of the above.
ocean tides are produced
A by the combined gravitational effects of the sun and moon
B by the moon only
C because the moon's gravitational force on the Earth is different at the no and south poles
D in such a way that there is one high tide and one low tide per day
all of the boundaries of the major moving tectonic plates on the Earth's surface are coincident with
A regions where ocean depths are greatest
B the edges of the continental shelves around the major continents
C the occurrence of major auroral activity
D the positions of maximum Earthquake occurrence
continental drift is caused by
A fluctuations in the Earth's magnetic field.
B large scale oceanic currents.
C tidal forces from the moon.
D convection in the Earth's mantle.
the nitrogen in the Earth's atmosphere came originally from
A the initial atmosphere of the Earth
B the solar wind
C the break-up of ammonia (nh4)
D out gassing from the interior
what gas makes up most of the Earth's atmosphere
A oxygen
B carbon dioxide
C nitrogen
D methane
astronomers sometimes refer to the Earth and moon as a "double planet."t might be because
A they are relatively similar in diameter and mass
B they are so close together
C no other planet has only one moon
D they orbit the sun in the same plane
one reason we infer that the Earth's core is metallic is that
A the average density is greater than the surface density.
B the surface density is greater than the average density.
C most of the Earth's surface is covered with water.
D most of the continents are made of metals.
E Earthquakes can only occur if the core is metallic.
the Earth's seasons are caused by
A the eccentricity of its orbit
B the 23 degree tilt of its axis
C its proximity to the sun
D the tides
destruction of the amazon jungle is reducing the amount of ______ in the atmosphere and increasing the amount of ______.
A carbon dioxide, oxygen
B oxygen, carbon dioxide
C nitrogen, oxygen
D carbon dioxide, nitrogen
auroras (or northern and southern lights) are caused primarily by
A sunlight reflected and refracted by the ice caps on both poles of the Earth
B atoms glowing in the upper atmosphere after being excited and ionized by UV radiation from the sun
C atoms glowing in the upper atmosphere after being hit by fast electrons from the magnetosphere
D the heating of atoms in the upper atmosphere by intense electrical currents
the Earth is thought to have formed from
A the collapse of a single gas cloud
B the consolidation (fusion) of small rock-like bodies
C gas which was torn from the sun
D the break-up of a much larger body
if the Earth's spin axis were to be perpendicular to the Earth's orbital plane (the ecliptic plane), the seasons and seasonal variation
A would remain the same in severity as they are at present but each season would last twice as long
B would be non-existent
C would remain the same as they are at present
D would become much more severe
what does current evidence indicate about the Earth's magnetic field in the past?
A it has always been essentially like it is now.
B it has undergone drastic changes and reversals.
C it has varied somewhat but not drastically.
D there is no way we can determine the Earth's magnetic history.
the major layers of the Earth's atmosphere from the surface upwards incorrect order, are
A stratosphere, mesosphere, thermosphere, troposphere
B mesosphere, troposphere, thermosphere, stratosphere
C thermosphere, mesosphere, troposphere, stratosphere
D troposphere, stratosphere, mesosphere, thermosphere
the primary constituent of the Earth's crust is:
A iron compounds.
B compounds of nitrogen.
C silicate compounds.
D hydrocarbons.
the primary constituent of the Earth's atmosphere at the surface is:
A hydrogen.
B helium.
C oxygen.
D nitrogen.
the lithosphere is
A a lithium-rich region of the Earth's crust
B a region of the atmosphere between the troposphere and the stratosphere
C the region above the ionosphere
D the crust and upper mantle
suppose the amount of carbon dioxide in the Earth's atmosphere decreased by a significant amount. what would happen to the Earth's general environment?
A x-rays from space would reach the Earth's surface.
B ultraviolet light from space would reach the Earth's surface.
C the average surface temperature would probably increase.
D the average surface temperature would probably decrease.
the process which produced the Earth's iron core is known as
A plate tectonics
B differentiation
C global subsidence
D intercalary addition
considering rotation rates and internals structure, the Earth's magnetic field should be
A much stronger than that on Venus and Mars.
B about the same as the Martian magnetic field, and much stronger than the magnetic field on Venus.
C about the same as the magnetic field of Venus, and much stronger than the field on Mars.
D weaker than the magnetic fields on Venus and Mars.
the Earth's atmosphere affects astronomical observations by
A turbulence that limits the seeing.
B absorbing some of the light that passes through it.
C scattering red light more than blue.
D (a) and (b)
E (b) and (c)
the Earth's atmosphere is composed mostly of
A oxygen
B carbon dioxide
C nitrogen
D hydrogen
the Earth's atmosphere interferes with astronomical observations because
A some wavelengths are absorbed by the atmosphere
B weather may make observation impossible
C it makes stars twinkle
D all of the above
the core of the Earth is probably made of
A iron and iron alloys.
B low density silicates.
C high density silicates.
D molten rock.
E uranium and lead.
the Earth's core is more dense than the crust or mantle. this fact can be used to infer what about the Earth's history?
A the metals accreted first and then the silicates.
B gravity has compacted the core and made it denser.
C the entire Earth was molten at one time.
D the sun heated the Earth more in the past then now.
E the Earth formed billions of years ago.
Earth's first atmosphere was
A generated by volcanic out gassing
B blown off by the solar gale
C produced by algae in the ocean
D largely a hydrogen-oxygen composition
Earth tides are caused primarily by the moon because:
A it exerts the greatest gravitational force on the Earth.
B it rotates synchronously.
C the tide raising force is a differential force.
D the moon is solid and the sun is gaseous.
the most prevalent element in the crust of the Earth is
A oxygen
B nitrogen
C sulfur
D silicon
seventy-five percent of the Earth's atmosphere is in the bottom region, which is called the
A troposphere
B stratosphere
C mesosphere
D thermosphere
the magnetic field of the Earth
A is a consequence of biologic activity
B protects the Earth from cosmic rays
C is radioactive and dangerous for astronauts to fly through
D acts as a shield against ultraviolet sunlight
the Earth's original atmosphere
A had no oxygen.
B consisted of light elements like hydrogen and helium.
C escaped into space.
D all of the above.
the mid-atlantic ridge is being produced by
A two tectonic plates pushing together, producing upthrust
B two tectonic plates moving apart, producing volcanic upflow
C the weight of the atlantic ocean on the thin seabed
D tidal flow of ocean water meeting in mid-atlantic
the age of the Earth is estimated at roughly
A 4.6 thousand years.
B 4.6 million years.
C 4.6 billion years.
D older than 10 billion years.
E younger than a few thousands years.
evidence that the Earth's interior was molten at one time is found in
A volcanic activity along midoceanic ridges.
B the composition of the atmosphere.
C the layers of different density within the interior.
D all of the above.
E only (a) and (b) above.
seasonal variations on the planet's surface occur because
A volcanoes periodically cloud out the atmosphere of planets, because of tidal interactions and distortions
B the planet's distance from the sun varies periodically over the orbital plane
C the planet's axis of spin is tilted with respect to the perpendicular to the orbital plane
D clouds alternately form and decay away, in a periodic way
the Earth's atmosphere has a large percentage of oxygen compared to that of the other terrestrial planets. the main source of this atmospheric oxygen was
A the breathing of animals over billions of years.
B release of oxygen by plants over many years.
C volcanic out gassing from the Earth's crust.
D a part of the atmosphere since the time of formation.
E a result of sea floor spreading and continental drift.
which of the following points is the strongest evidence that the Earth is the most evolved of the terrestrial planets?
A it has liquid water on its surface.
B it has the highest surface gravity.
C it has the lowest percentage of carbon dioxide in the air.
D it has the most geologic activity now.
E it has the largest moon.
the most common gas in the Earth's early atmosphere is thought to have bee
A oxygen
B hydrogen
C water
D carbon dioxide
the source of the energy for plate tectonics is
A tidal stress on the crust of the Earth due to the moon
B centrifugal force due to the Earth's rapid rotation
C internal heat generated by radioactive elements
D continuing internal differentiation as iron sinks slowly to the core
large scale changes on the surface of Earth are probably caused by
A wind erosion
B continental drift
C glaciation
D water erosion
the youngest parts of the Earth's crust are
A the midocean rifts.
B the continents.
C the continental margins.
D none of these.
the greenhouse effect heats a planet because
A more sunlight strikes the planet's surface than normal.
B the surface of the planet is darker than normal.
C infrared radiation is trapped by the planet's atmosphere.
D cloud cover prevents the atmosphere from escaping.
E cloud cover prevents visible light from striking the surface.
seasons on Earth are due to
A the tilt of the Earth's orbital plane
B the tilt of the Earth's rotational axis
C the variation of the Earth's distance to the sun
D none of the above
the van allen belts are
A faint halos of interplanetary dust between moon and Earth
B zones on the Earth where seismological waves from an Earthquake are not felt
C layers of the Earth's atmosphere between troposphere and stratosphere
D regions of intense charged particles trapped within the Earth's magnetosphere
the layer of atmosphere which contacts the Earth's surface is the
A ionosphere
B stratosphere
C mesosphere
D troposphere
the basic colors of Earth as seen from outer space are
A blue and white
B green and brown
C grey and white
D brown
the Earth's magnetic field is due to the existence of:
A a magnetic dipole in the interior.
B an interior temperature above the curie temperature.
C circulation in the molten outer core.
D an unknown source.
the mid-atlantic ridge in the Earth's crust is a region where
A two tectonic plates are slowly spreading apart
B two tectonic plates are pushing against one another, forcing the ridge upwards
C one tectonic plate is moving below another (subducting)
D a single hot plume is pushing molten magma or lava through a hole in the crust
what is responsible for the high oxygen content of the Earth's atmosphere?
A the regular outpouring of oxygen from volcanoes
B the slow seeping up of oxygen from inside the Earth through Earthquake faults
C the ionosphere
D the activity of living organisms
which of the following is not a region of the Earth's atmosphere or near environment?
A chromosphere
B stratosphere
C troposphere
D magnetosphere
summertime in the northern hemisphere is when
A the Earth is closest to the sun
B the clearest skies occur, because of climate
C sunlight falls more directly upon Earth, thereby heating it and indirectly the Earth's atmosphere, by a greater amount than average
D sunlight heats the atmosphere the maximum amount by passing through it at an oblique
angle
the Earth's magnetic field, and hence the magnetic polar axis
A has been constant and fixed throughout geological history
B is moving and changing continuously with time, and occasionally reversing
C is constant and fixed now, but moved and changed in very early geological time
D remains absolutely constant for long periods (approximately 100,000 years) and then
suddenly reverses in direction
the half-life of an element refers to
A the time it takes for half the amount of the element to grow in a rock
B the fact that the Earth, together with its elements, is middle-aged
C the time required for half of the nuclei of a sample to decay
D none of the above
high tide occurs on the side of the Earth opposite the moon because
A the moon pulls more strongly on the Earth than the water on that side
B the moon's gravitational force pushes the water away
C centrifugal force on the water causes it to "swing out" away from the Earth
D it counterbalances the high tide on the side toward the moon
the magnetic field of the Earth is believed to originate from which of the following causes?
A permanent magnetism present since the formation of the Earth
B electrical currents surrounding the Earth like the van allen belts
C convective currents in the liquid portion of the Earth's core
D the cause is completely unknown to science at present
which of the following is true about the Earth's atmosphere?
A it is a secondary atmosphere that formed from venting of the interior long after the Earth formed.
B it evolved directly from the primordial atmosphere.
C it is the same as it was when the Earth was formed billions of years ago.
D we have no idea how the present atmosphere formed.
the overall structure of the Earth's magnetic field is that of
a a single pole at the north magnetic pole.
B dipole with opposite north and south poles.
C diffuse field with no poles at all.
D single pole at the south magnetic pole.
E none of the above.
the Earth's magnetic field probably arises from
A human activity.
B circulation in the Earth's atmosphere.
C currents in the Earth's liquid, conducting outer core.
D currents in the oceans.
which of the following is not one of the probable stages in the development of the Earth?
A melting of its surface.
B condensation of its primordial atmosphere.
C differentiation.
D thin lithospheric tectonics and volcanism.
the magnetic field of the Earth is thought to be caused by
A localized magnetic anomalies near the Earth's surface
B motions of molten material in the Earth's interior causing a dynamo effect
C a magnetized solid iron core in the Earth's interior
D the flow of solar wind particles around and within the Earth's outer atmospheric region,
the magnetosphere
subduction on the Earth is the process by which
A dense material sank while lighter material rose to the surface during the early geological history of the Earth
B molten lava oozes out between two tectonic plates which are spreading apart
C surface material on Earth sinks below other material at a tectonic plate boundary
D volcanic material comes out from the deep interior at a volcanic island' s as Hawaii
suppose the amount of carbon dioxide in the Earth's atmosphere decreased by a significant amount. what would happen to the Earth's general environment
A x-rays from space would reach the Earth's surface
B ultraviolet light from space would reach the Earth's surface
C the average surface temperature would increase
D the average surface temperature would decrease
the chemical constituent which absorbs UV radiation in the intermediate layers of the atmosphere of Earth is
A n2
B co2
C h20, water vapor
D ozone, o3
the greenhouse effect on the Earth's atmosphere is the
A trapping of infrared radiation from the warm Earth by the atmosphere
B shielding of life forms from solar ultraviolet radiation by the ozone layer
C accentuated growth of plants near the equator, compared to the growth intemperate zones
D capturing the visible and ultraviolet radiation from the sun by the atmosphere, thereby
warming it
the presence of oxygen in the Earth's atmosphere is thought to result directly from what type of process?
A volcanic eruptions
B out gassing of the oceans
C the original condensation of interplanetary gas clouds
D biological activity
craters in the abundance seen on the moon are not apparent on Earth at the present time because
A all the potentially damaging interplanetary bodies were stopped by the Earth's atmosphere
B the moon protected the Earth from impacts, and this resulted in the craters and maria on the moon
C plate tectonics has returned cratered surface layers into the Earth's interior, and weathering has obliterated the more recent craters
D interplanetary objects have avoided the Earth during its history
the source of oxygen for the Earth's atmosphere is probably
A the breakdown of water into hydrogen and oxygen.
B biological activity, such as photosynthesis.
C out gassing from the Earth's interior.
D the release of carbon dioxide by volcanoes.
the gas temperature in the stratosphere of the Earth's atmosphere reaches a maximum at about 50 km. the cause of this is
A heating by auroral activity higher in the atmosphere
B turbulence, caused by wind and weather
C absorption of ultraviolet radiation by ozone, 03
D ionization of o2 and n2, by solar ultraviolet radiation
how do seismic waves tell us that part of the Earth's core is molten?
A all seismic waves are transmitted by the core.
B all seismic waves are completely absorbed by the core.
C some seismic waves are absorbed by the core while others are transmitted by it.
D seismic waves are amplified by the core.
in the modern theory of crustal motion on the Earth's surface, the process of sea-floor spreading is described as
A the motion of plates away from mid-oceanic ridges and towards continental boundaries
B the rotation of plates around axes which remain stationary on the Earth, causing plate-edge collisions
C the motion of plates towards mid-oceanic ridges and away from continental boundaries
D the upward motions of some plates, and the downward motions of others while remaining
in fixed positions on the Earth
the most common rocks on the Earth's surface are
A oxides
B halides
C silicates
D sulfides
if indeed the Earth has the same total amount of carbon dioxide as Venus, why is such a small amount found in the atmosphere?
A the statement is false -- Venus and the Earth do not have the same total amount of carbon dioxide
B the statement is false -- the amount of carbon dioxide in the atmosphere of the Earth is the same as for Venus' atmosphere
C the plants on Earth have decreased the amount of carbon dioxide to where I is today
D the Earth's lower temperature allows the carbon dioxide to be held in the oceans and rocks
in the troposphere how does the temperature vary as the altitude increases?
A the temperature of the troposphere is nearly constant.
B the temperature of the troposphere decreases with increased altitude.
C the temperature of the troposphere increases with increased altitude.
D we don't know how the temperature of the troposphere varies.
the most prevalent element in the Earth's atmosphere is
A hydrogen
B helium
C oxygen
D nitrogen
the core of Earth is composed mainly of
A iron and nickel
B radioactive ash
C helium and hydrogen
D water, because it is liquid
on the Earth, the majority of Earthquakes occur
A in the centers of tectonic plates (e.g., north american continent)
B along the boundaries of major tectonic plates
C in the arctic and antarctic regions
D along the zone of maximum tidal stress around the equator
the magnetic field of the Earth is caused by
A a solid iron magnet inside the Earth
B currents flowing in the high atmosphere (ionosphere) of the Earth
C the motion of the solar wind blowing by the Earth
D currents of molten iron flowing in the core
the level of the atmosphere which consists of charged particles is the
A troposphere
B ionosphere
C mesosphere
D stratosphere
the motions of large portions of the Earth's surface, the "plates", are caused by
A flexing of the surface due to solar heating and nighttime cooling
B the varying pressure of the Earth's atmosphere, both daily and seasonally
C tidal flow in oceanic waters
D convective flow in matter in the Earth's interior
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