National Earth Science Olympiad Sample Questions [SET II]

ATMOSPHERE

1. Which is the innermost layer of atmosphere?

       a) Lithosphere.
       b) Stratosphere.
       c) Troposphere.
       d) Biosphere.

2. When traveling by air, your airplane flies through this zone of atmosphere:

       a) Higher part of the Troposphere not beyond.

       b) Mainly the lower part of the Stratosphere.

       c) Lower part of the Mesosphere.

       d) None of the above.

3. Ozone molecules useful in blocking UV rays of the sun are dispersed at this altitude from the surface of earth:

         a) Only near the surface.

         b) From surface to 11 Kms.

         c) From 11 Kms to 30 Kms.

         d) From 31 to 50 Kms.

4. The temperature in the Stratosphere increases with height as compared to Troposphere because:

        a). Both contain Ozone but concentration of ozone is higher in Stratosphere than in Troposphere

        b)  Sun is closer to stratosphere compared to troposphere.

        c) Clouds are present in Troposphere which cool the later.

        d) None of the above.

5. How much of the earth’s air is found in the atmosphere inner most layer (troposphere)

        a) 75 %

        b) 80 %

        c) 65 %

        d) 57 %

6.Which layer of the atmosphere is known as global sunscreen?

        a) Troposphere.

        b) Stratosphere.

        c) Mesosphere.

        d) Thermosphere

7. Which are the chemical constituents found in Exposphere? A. Helium.

        a) Ozone.

        b) Oxygen

        c) Methane

       d) Helium.

8. The transitional region between the the atmosphere and vacuum of inter planetary space is called?

        a) Troposphere.

        b) Stratosphere.

        c) Mesosphere.

        d) Exosphere.

       9. The layer of the earth the reflects radio wave back to earth is called?

        a) Ionosphere

        b) Radiation zone

        c) Aurora borealis

        d) Ozone layer

10. In the atmosphere, tiny solid or liquid suspended particles of various composition are called?

        a) Aerosols

        b) Carcinogens

        c) Greenhouse Gases

        d) Microbes

HYDROSPHERE

1. Precipitation is usually expressed in which of the following units?

1. ml    
2. g/m²   
3. mm     
4. m³

2.  Which of the following is not a method of estimating river discharge?

1. Dilution Gauging  
2. Atmometer readings  
3. Rating Curve  
4. Velocity-Area Method

3.  Which of the following does not apply to infiltration excess overland flow?

1. Common in semi-arid areas where soil surface crusts develop
2. Rare in areas subject to extreme rainfall events
3. Common where the surface is often frozen
4. Rare in many temperature areas because infiltration capacity is too high

4.  Which of the following is not one of the major paths for water entering the soil?

1. Percolates into bedrock 
2. Infiltration-excess overland flow
3. C. Taken up by plants and   transpired   
4. Travels laterally through the soil

5.  What does a 'hydrograph' display?

1. Variations in water temperature against discharge 
2. Variations in river discharge over time
3. Variations in sediment concentration against river discharge
4. Variations in snowfall over time

6. Which of the following statements is not correct with respect to river flow in dry land environments?

1. Dry lands are characterized by rare but intense rainfall events
2. Most of the water is stored above ground to maintain base flow until the next flood event
3. Coarse and sandy soil often results in high infiltration capacities 
4. The intense nature of rainfall events causes rapid runoff and high flood peaks

7. Which of the following is the most likely impact of deforestation and increased grazing intensity?

1. Increased infiltration capacity and greater base flow contribution
2. Reduced infiltration capacity and greater infiltration-excess overland flow generation
3. Reduced annual river flow
4. Increased precipitation input

8. In the context of river flows in glacial regions, which of the following is not correct?

1. Large snow/ice melt input in early winter causes high flood potential
2. Discharge can be extremely low over winter
3. Outputs in the water budget often do not equal inputs due to a large amount of long term           water storage
4. Discharge is lower at night than during the daytime

9. In which of the following through flow pathways does water travel through the finest soil pores?

1. Stomatal pore flow
2. Matrix flow
3. Pipe flow
4. Macropre flow

10. Approximately what percentage of the earth's surface is covered by oceans?

1. 10%  
2. 35%  
3. 71%  
4. 90%

11.  Rising levels of atmospheric carbon dioxide will cause which of the following changes in oceanic chemistry?

1. Increased salinity 
2. Decreased pH
3. Decreased salinity
4. Increased precipitation of calcium carbonate

12. Which two features together control the density of seawater?

1. Salinity and depth
2. Temperature and sea depth
3. Temperature and salinity
4. Salinity and plankton concentration

13. Surface ocean currents are driven mainly by which of the following?

1. Salinity gradients
2. Prevailing winds
3. Temperature gradients
4. Warm Air

14. Deep ocean currents are driven mainly by which of the following?

1. Prevailing winds
2. Temperature and salinity gradients
3. Mid-ocean ridge volcanism
4. Earth’s rotation

15. Which of the following reservoir contains the most water?

1. Atmosphere  
2. Biosphere
3. Groundwater   
4. Lake and Rivers

16. The main parts of the water cycle are evapotranspiration, precipitation, and

1. Evaporation
2. Condensation
3. Runoff
4. Deposition

17.  Condensation is a change in water from a

1. Solid to liquid
2. Liquid to solid
3. Gas to liquid
4. Liquid to gas

18. All the sediment carried by a river is called the

1. Suspended load
2. Bed load
3. Stream load
4. Dissolved load

19. An aquifer contains a great deal of water, but the water cannot be removed easily with an ordinary well. This is most likely due to sediment and rock characterized by

1. Low porosity
2. Low permeability
3. Poor sorting
4. High iron content

20. The water table forms the upper surface of the

1. Cap rock layer
2. Contour surface
3. Zone of saturation
4. Artesian formation

21. Which of the following statements about groundwater is true?

1. Groundwater is a nonrenewable resource.
2. Groundwater can be replenished by pumping sea water into the ground.
3. Once groundwater is polluted it can never be used again
4. Groundwater can be conserved by recycling used water.

 22. Drainage basins are also called

1. Floodplains
2. Whirlpools
3. Watersheds
4. Artesian wells

23.  The attraction of water molecules to other materials, such as soil, is called

1. Permeability
2. Gradient
3. Porosity
4. Capillary action

24. One of the major disadvantages of hard water is that it

1. Cannot be used for drinking
2. Inhibits the flow of water up through artesian wells
3. Contaminates groundwater aquifers
4. Damages appliances due to the buildup of mineral deposits

25. When water freezes it

1. Decreases in volume
2. Becomes denser causing ice to sink
3. Increased in volume, which causes ice to float.
4. No phase change occurs

26.  Because water become less dense when the temperature moves from 4o C to 0o C water that is near the freezing point will be found

1. On the surface of a lake
2. On the bottom of a lake
3. At the mid-level of a lake
4. Only next to the shore.

27. Water is called the universal solvent because

1. Water dissolves nothing
2. Water dissolves more substances than any other solvent.
3. Water dissolves everything
4. None of the above

28. Properties that make water feel wet are

1. Adhesion
2. Cohesion
3. A and B
4. None of the above

29. Cohesion properties of water allow

1. Some spiders to walk on water
2. Wood to float
3. Water to dissolve sugar
4. Water to cool out bodies

30.  Capillary action of water is caused by

1. Adhesion and cohesion properties
2. Adhesion properties only
3. Solvent properties of water
4. Water's specific heat

31. Phase changes of water occur when

1. Liquid changes to ice
2. Ice changes to liquid
3. Liquid changes to steam
4. All of the above

32. Energy is lost from water when

1. Ice changes to liquid
2. Liquid changes to steam
3. The water temperature increases
4. Steam changes to liquid

33. The unique properties of water are mostly the result of?

1. Ionic bonds
2. Atomic bonds
3. Hydrogen bonds
4. Covalent bonds

34.  The unique properties of water are important to?

1. Ecology of lakes, streams, and oceans
2. Plants the use water to transport nutrients
3. Animals whose blood must contain water to move all chemicals they need to survive
4. All of the above.

 35. Which body of water has the highest salinity?

1. Mediterranean Sea
2. Red Sea
3. Baltic Sea
4. Black Sea

36. Which feature is at the greatest depth in the ocean?

1. Abyssal plain
2. Continental shelf
3. Submarine canyon
4. Continental rise

37. What is transported through the ocean in turbidity currents?

1. Nutrients
2. Oxygen
3. Salts
4. Sediments

38. At what temperature does fresh water have its maximum density?

1. 0 degree C.
2. 4 degrees C
3. 32 degrees C
4. 100 degrees C

 39. A river flows into a quiet lake and begins to form a  __________________?

1. Delta
2. Alluvial fans
3. Natural levees
4. Point bars

40. About how much dissolved materials do rivers transport each year?

1. 2-4 thousand tons
2. 2-4 million tons
3. 2-4 billion tons
4. 2-4 trillion tons

41. The primary source of energy for the earth's atmosphere?

A. Energy from within the earth

B. The sun

C. Erupting volcanoes

D. Lightning discharges associated with thunderstorms

42. The most abundant gases in the earth's atmosphere by volume are:

A. Carbon dioxide and nitrogen

B. Oxygen and water vapor

C. Nitrogen and oxygen

D. Oxygen and helium

43. Water vapor is:

A. A gas

B. A cloud droplet

C. A rain drop

D. A snowflake

44. Which of the following is considered a variable gas in the earth's atmosphere?

A. Water vapor

B. Nitrogen

C. Oxygen

D. Argon

45. The gas that shows the most variation from place to place and from time to time in the lower atmosphere:

A. Ozone (O3)

B. Carbon dioxide (CO2)

C. Water vapor (H2O)

D. Methane (CH4)

46. In the atmosphere, tiny solid or liquid suspended particles of various composition are called:

A. Aerosols

B. Carcinogens

C. Greenhouse gases

D. Microbes

47. The most abundant greenhouse gas in the earth's atmosphere:

A. Carbon dioxide (CO2)

B. Nitrous oxide (N2O)

C. Water vapor (H2O)

D. Methane (CH4)

48. Which of the following processes acts to remove carbon dioxide from the atmosphere?

A. Lightning

B. Deforestation

C. Photosynthesis

D. Burning fossil fuels

49. The earth's first atmosphere was composed primarily of?

A. Carbon dioxide and water vapor

B. Hydrogen and helium

C. Oxygen and water vapor

D. Argon and nitrogen

50. The most abundant gas emitted from volcanoes?

A. Nitrogen

B. Sulfur dioxide

C. Helium

D. Water vapor

51. This holds a planet's atmosphere close to its surface?

A. Radiation

B. Gravity

C. Cloud cover

D. Moisture

52. The amount of force exerted over an area of surface is called?

A. Density

B. Weight

C. Temperature

D. Pressure

53. Which of the following weather elements always decreases as we climb upward in the atmosphere?

A. Wind

B. Temperature

C. Pressure

D. Moisture

54. The gas responsible for the greenhouse effect on Venus?

A. Carbon dioxide (CO2)

B. Oxygen (O2)

C. Ozone (O3)

D. Nitrogen (N2)

55. The planet with a strong greenhouse effect, whose surface temperature averages 480 Degrees C (900 Degrees F)?

A. Earth

B. Venus

C. Mars

D. Pluto

56. The earth's atmosphere is divided into layers based on the vertical profile of?

A. Air pressure

B. Air temperature

C. Air density

D. Wind speed

57. Almost all of the earth's weather occurs?

A. Exosphere

B. Stratosphere

C. Mesosphere

E. Troposphere

58. The hottest atmospheric layer?

A. Stratosphere

B. Mesosphere

C. Thermosphere

D. Troposphere

59. The atmospheric layer in which we live is called?

A. Troposphere

B. Stratosphere

C. Thermosphere

D. Ionosphere

60. The instrument that measures temperature, pressure, and humidity at various altitudes in the atmosphere?

A. Barograph

B. Radiosonde

C. Aneroid barometer

D. Altimeter

ENVIRONMENTAL SCIENCE

72. Many individuals of the same species living together in a defined area form a/an

A. Community

B. Ecosystem

C. Genus

D. Population

73. Which of the following is characteristic of parasitism?

A. One organism lives in or on another and benefits. 

B. Two organisms nourish each other; both benefit.

C. One organism kills and consumes another.

D. Two organisms live together and neither is harmed.

74. The sequence of energy flow through a food chain is 

A. primary consumers‑ producers‑ higher order consumers.

B. producers‑ higher order consumers‑ primary consumers.

C. producers‑ primary consumers‑ higher order consumers. 

D. primary consumers‑ higher order consumers‑ producers.

75.  The two compounds that acid rain contains that are most damaging to the environment are ____________ and ____________.

A. nitrogen; water

B. carbon dioxide; sulfuric acid

C. sulfur dioxide; nitrogen oxides

D. carbon dioxide; water

76. The only gas in the atmosphere that can absorb the sun's dangerous ultraviolet radiation is ____.

A. nitrogen

B. ozone

C. nitrous oxide

D. carbon dioxide

77. The largest amount of usable water found on earth is used for ___.

A. household use

B. crop irrigation

C. recreation

D. industrial uses

78. Which of the following are producers?

A. termites

B. bacteria

C. algae

D. all of the above

79. What is happening to the amount of carbon dioxide in the atmosphere?

A. it is increasing

B. it is decreasing

C. it is steady

D. it is fluctuating

80.  The major reservoir for phosphorus is

A. aquifers

B. clouds

C. the atmosphere

D. soil and rocks 

81. Precipitation is usually expressed in which of the following units?

A. ml    

B. g/m²   

C. mm    

D.m³

82.  Which of the following is not a method of estimating river discharge?

A. Dilution Gauging  

B. Atmometer readings  

C. Rating Curve  

D.Velocity-Area Method

83. Which of the following does not apply to infiltration excess overland flow?

A. Common in semi-arid areas where soil surface crusts develop

B. Rare in areas subject to extreme rainfall events

C. Common where the surface is often frozen

D.Rare in many temperature areas because infiltration capacity is too high

84.  Which of the following is not one of the major paths for water entering the soil?

A. Percolates into bedrock 

B. Infiltration-excess overland flow

C. C. Taken up by plants and   transpired   

D.Travels laterally through the soil

85.  What does a 'hydrograph' display?

A. Variations in water temperature against discharge 

B. Variations in river discharge over time

C. Variations in sediment concentration against river discharge

D.Variations in snowfall over time

86. Which of the following statements is not correct with respect to river flow in dry land environments?

A. Dry lands are characterized by rare but intense rainfall events

B. Most of the water is stored above ground to maintain base flow until the next flood event

C. Coarse and sandy soil often results in high infiltration capacities 

D.The intense nature of rainfall events causes rapid runoff and high flood peaks

87. Which of the following is the most likely impact of deforestation and increased grazing intensity?

A. Increased infiltration capacity and greater base flow contribution

B. Reduced infiltration capacity and greater infiltration-excess overland flow generation

C. Reduced annual river flow

D.Increased precipitation input

88. In the context of river flows in glacial regions, which of the following is not correct?

A. Large snow/ice melt input in early winter causes high flood potential

B. Discharge can be extremely low over winter

C. Outputs in the water budget often do not equal inputs due to a large amount of long term           water storage

D.Discharge is lower at night than during the daytime

89. In which of the following through flow pathways does water travel through the finest soil pores?

A. Stomatal pore flow

B. Matrix flow

C. Pipe flow

D.Macropre flow

90. Approximately what percentage of the earth's surface is covered by oceans?

A. 10%  

B. 35%  

C. 71%  

D.90%

91.  Rising levels of atmospheric carbon dioxide will cause which of the following changes in oceanic chemistry?

A. Increased salinity 

B. Decreased pH

C. Decreased salinity

D.Increased precipitation of calcium carbonate

92. Which two features together control the density of seawater?

A. Salinity and depth

B. Temperature and sea depth

C. Temperature and salinity

D.Salinity and plankton concentration

93. Surface ocean currents are driven mainly by which of the following?

A. Salinity gradients

B. Prevailing winds

C. Temperature gradients

D.Warm Air

94. Deep ocean currents are driven mainly by which of the following?

A. Prevailing winds

B. Temperature and salinity gradients

C. Mid-ocean ridge volcanism

D.Earth’s rotation

95. Which of the following reservoir contains the most water?

A. Atmosphere  

B. Biosphere

C. Groundwater   

D.Lake and Rivers

96.  The main parts of the water cycle are evapotranspiration, precipitation, and

A. Evaporation

B. Condensation

C. Runoff

D.Deposition

97.  Condensation is a change in water from a

A. Solid to liquid

B. Liquid to solid

C. Gas to liquid

D.Liquid to gas

98. All the sediment carried by a river is called the

A. suspended load

B. bed load

C. stream load

D.dissolved load

99.  An aquifer contains a great deal of water, but the water cannot be removed easily with an ordinary well. This is most likely due to sediment and rock characterized by

A. low porosity

B. low permeability

C. poor sorting

D.high iron content

100. The water table forms the upper surface of the

A. cap rock layer

B. contour surface

C. zone of saturation

D.artesian formation

ATMOSPHERIC PHYSICS

201. Solar radiation reaches the earth's surface as?

A.       Visible radiation only

B.       Ultraviolet radiation only

C.       Infrared radiation only

D.       Ultraviolet, visible, and infrared radiation

202. Electromagnetic radiation with wavelengths between 0.4 and 0.7 micrometers is called?

A.       Ultraviolet light

B.       Visible light

C.       Infrared light

D.       Microwaves

203. The blueness of the sky is mainly due to?

A.       The scattering of sunlight by air molecules

B.       The presence of water vapor

C.       Absorption of blue light by the air

D.       Emission of blue light by the atmosphere

204. If the average temperature of the sun increased, the wavelength of peak solar emission would?

A.       Shift to a shorter wavelength

B.       Shift to a longer wavelength

C.       Remain the same

D.       Impossible to tell from given information

205. The proper order from shortest to longest wavelength is:

A.       Visible, infrared, ultraviolet

B.       Infrared, visible, ultraviolet

C.       Ultraviolet, visible, infrared

D.       Visible, ultraviolet, infrared

206. Warming in the stratosphere is mainly caused by?

A.     Absorption of ultraviolet radiation by ozone

B.     Release of latent heat energy during condensation

C.     Chemical reactions between ozone and chlorofluorocarbons

D.     Frictional heating caused by meteorites

207. In a temperature inversion:

A.       Air temperature increases with increasing height

B.       Air temperature decreases with increasing height

C.       Air temperature remains constant with increasing height

D.       It is warmer at night than during the day

208. The rate at which temperature decreases with increasing altitude is known as the:

A.       Temperature slope

B.       Lapse rate

C.       Sounding

D.       Thermocline

209. The electrified region of the upper atmosphere is called the:

A.       Thermosphere

B.       Mesosphere

C.       Stratosphere

D.       Ionosphere

210. The gas that absorbs most of the harmful ultraviolet radiation in the stratosphere?

A.       Water vapor

B.       Nitrous oxide

C.       Carbon dioxide

D.       Ozone

211. Which latitude belt best describes the middle latitudes?

A.       20o to 80o

B.       10o to 35o

C.       20o to 35o

D.       40o to 70o

212. The wind direction is:

A.       The direction from which the wind is blowing

B.       The direction to which the wind is blowing

C.       Always directly from high toward low pressure

D.       Always directly from low toward high pressure

213. The horizontal transport of any atmospheric property by the wind is called:

A.       Advection

B.       Radiation

C.       Conduction

D.       Latent heat

214. Which of the following determine the kind (wavelength) and amount of radiation that an object emits?

A.       Temperature

B.       Thermal conductivity

C.       Density

D.       Latent heat

215. Most of the radiation emitted by a human body is in the form of:

A.       Ultraviolet radiation and is invisible

B.       Visible radiation but is too weak to be visible

C.       Infrared radiation and is invisible

D.       Humans do not emit electromagnetic radiation

216. The sun emits its greatest intensity of radiation in:

A.       The visible portion of the spectrum

B.       The infrared portion of the spectrum

C.       The ultraviolet portion of the spectrum

D.       The x-ray portion of the spectrum

217. The earth's radiation is often referred to as ________radiation, while the sun's radiation is often referred to as _________radiation.

A.       shortwave, long wave

B.       shortwave, shortwave

C.       long wave, shortwave

D.       long wave, long wave

218. The earth emits radiation with greatest intensity at:

A.       Infrared wavelengths

B.       Radio wavelengths

C.       Visible wavelengths

D.       Ultraviolet wavelengths

219. Without the atmospheric greenhouse effect, the average surface temperature would be:

A.       Higher than at present

B.       Lower than at present

C.       The same as it is now

D.       Much more variable than it is now

220. The earth's atmospheric window is in the:

A.       Ultraviolet region

B.       Visible region

C.       Infrared region

D.       Polar regions

GEOLOGIC TIME

221. Fossils are most common in which rock types?

a. Sedimentary

b. Igneous

c. Metamorphic

d. All of these commonly contain fossils

222. A disconformity is ___________ .

a. Rock unit that does not contain fossils

b. An erosional surface between igneous and metamorphic rocks

c. An erosional surface between horizontal sedimentary rocks

d. An erosional surface between different rock types

223. Which of the following is used by geologists to determine the relative ages in a rock sequence?

a. Stratigraphy

b. Fossils

c. Cross-cutting relationships

d. All of these

224. Which of the following will not make a fossil?

a. Decomposed organic material

b. Plant impressions (casts)

c. Animal footprints

d. Loose animal bones

225. Most periods in the geologic time scale are named for _______.

a. Geographic localities

b. Fossils

c. Catastrophic events

d. Paleontologists

226. What scientific avenue of investigation gave scientists the best estimate of the age of the Earth?

a. Dating fossils

b. Archaeological dating

c. Radiometric dating

d. Carbon dating

227. Human beings evolved during which geologic era?

a. Cenozoic

b. Mesozoic

c. Paleozoic

d. Precambrian

228. Approximately how long ago did the Big Bang take place?

a. 10-15 thousand years ago

b. 10-15 million years ago

c. 100-150 million years ago

d. 10-15 billion years ago

229. the branch of geology that focuses on the study of fossils is_______

a. Paleotology

b. Fossilography

c. Taxonomy

d. Taphonomy

230. This era accommodated the development and growth of invertebrates

a. Paleozoic era

b. Cenozoic era

c. Mesozoic era

d. Jurassic period

231. With the threat of the big dinosaurs gone,

a. Plants grew taller  

b. Mammals thrived

c. It rained more

d. Large potholes became less of a problem

232. Scientists suggest the Himalayas were pushed up during which time?

 a. Paleozoic era

 b. Cenozoic era

 c. Mesozoic era

 d. Jurassic period

 233. Clair Patterson and Friedrich Houtermans separately found the age of the Earth by___________

 a. circumnavigating the globe in outrigger canoes

 b. finding and comparing the radioactive decay rates of isotopes of copper

 c. asking bright graduate students to help them

 d. finding and comparing the radioactive decay rates of isotopes of Lead

234. The supercontinent, Pangea, broke up into

 a. Pangea prime and sub-Pangea

 b. Laurasia and Gondwana

 c. India and Canada

 d. Antarctica and Holland

235. Geological time is measured in

  a. meters/second

  b. days/year

  c. geometric units

  d. geochronological units

236. Time that spans billions of years is known as

 (a) the beginning of the semester until the end

 (b) biological time

 (c) geological time

 (d) epidemiological time

 237. Between Archaen and Proterozoic, which is earlier?

 (a) Proterozoic

 (b) Archaen

 (c) scientists are still observing the protists

 (d) they are the same age

 

 238. Global ‘‘hot spots’’ of magma are thought to have caused

 (a) cracks in the super continent, Pangea

 (b) a thicker mantle

 (c) a change in vacation plans for early humans

 (d) a limited biosphere

 239. Rocks and fossils from the Precambrian eon are thought to be as much as

(a) 2 billion years old

(b) 3 billion years old

(c) 4 billion years old

(d) 5 billion years old

 240. What conditions promote fossilization?

 a. Rapid burial

 b. Lack of CO2

 c. Delayed Burial

 d. Abundance of Oxygen

 241. Compression is most common for _________

 a. fossils of leaves and ferns

 b. fossils of Marine Creatures

 c. fossils of Aeolian

 d. fossils of Fluvials.

 242. The possible depositional environment of the rock containing ammonite fossils was

 a. Fluvial

 b. Aeolian

 c. Glacial

 d. Marine

 243. The oldest fossil recorded on the earth is about ________ billion years old.

 a. 3

 b. 2

 c. 1

 d. 0.5

 244. A large number of animals got extinct at the end of the Cretaceous time. This extinction was caused by ________.

 a.  Meteorite impact;

 b. Tsunami;

 c. Volcanism;

 d. A and C

 245. Rocks containing fossils of __________ would be the oldest.

 a. Dinosaur bones;

 b. Trilobites;

 c. Bird bones;

 d. Woolly mammoth bones

 246. Paleoecology is________________

 247. Radiometric age is often referred to as __________ age.

 a. Total

 b. Absolute

 c. Historic

 d. Geologic

 248. An undeformed sedimentary layer is __________ than the layer above and _______ than the layer below.

 a. younger ---younger

 b. younger --- older

 c. older --- younger

 d. older --- older

 249. What is the name for an erosion surface that separates two sets of sedimentary layers with non-parallel bedding planes?

 a. cross-bedding

 b. formation

 c. angular unconformity

 d. fault

 250. A nonconformity is _________ .

 a. a rock unit that is different than units above or below it

 b. a gap in the geologic record bounded below by metamorphic or igneous rocks and bounded above by sedimentary rocks

 c. a rock unit that does not contain fossils

 d. a sequence of rocks that does not contain any gaps in the geologic record