Question 1a of 15 ( 3 Seismic Waves 261768 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Which leads scientists to believe that Earth's inner core is solid? Choice Feedback A. Only S waves travel through Earth's inner core. P and S waves can both travel through solids. B. The inner core is less dense than the outer core. This does not indicate that the inner core is a solid. C. Only P waves travel through Earth's inner core. P and S waves can both travel through solids. *D. Waves traveling through the inner core go faster than those through the outer core. That's correct! Global Incorrect Feedback The correct answer is: Waves traveling through the inner core go faster than those through the outer core. -------------------------------------------------------------------------------- Question 1b of 15 ( 3 Seismic Waves 261108 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: How does Earth's solid inner core affect seismic waves? Choice Feedback A. It blocks S waves from passing through. P and S waves can both travel through solids. B. They go slower through the inner core than the liquid outer core. This is not true. C. It blocks P waves from passing through. P and S waves can both travel through solids. *D. They go faster through the inner core than the liquid outer core. That's correct! Global Incorrect Feedback The correct answer is: They go faster through the inner core than the liquid outer core. -------------------------------------------------------------------------------- Question 1c of 15 ( 3 Seismic Waves 261110 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Which is used by scientists as evidence that Earth's inner core is solid? Choice Feedback A. S waves cannot travel through the inner core, creating a shadow zone. P and S waves can both travel through solids. B. The inner core is composed of nickel, while the outer core is composed of iron. This does not indicate that the inner core is a solid. C. P waves cannot travel through the inner core, creating a shadow zone. P and S waves can both travel through solids. *D. Seismic waves change speed when they go from the inner core to the outer core. That's correct! Global Incorrect Feedback The correct answer is: Seismic waves change speed when they go from the inner core to the outer core. -------------------------------------------------------------------------------- Question 2a of 15 ( 2 Magnets and Compasses 166226 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Which statement is true of magnets? Choice Feedback A. Earth is a permanent magnet. Earth is not a permanent magnet. Its magnetism is due to electromagnetism. B. Electromagnets are generally weaker than permanent magnets. Electromagnets can actually be much stronger than permanent magnets. *C. A magnet always has two poles. That's correct! D. Electromagnets always have the same strength. Electromagnets can change in strength much more easily than permanent magnets. Global Incorrect Feedback The correct answer is: A magnet always has two poles. -------------------------------------------------------------------------------- Question 2b of 15 ( 2 Magnets and Compasses 261111 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Which statement is true of magnets? Choice Feedback A. Earth is a permanent magnet with two poles. Earth is not a permanent magnet. Its magnetism is due to electromagnetism. B. A magnet can have one or two poles. Magnetic always have two poles. *C. Electromagnets can be made much stronger than permanent magnets. That's correct! D. Electromagnets cannot be turned on and off. Electromagnets can be turned on and off. Global Incorrect Feedback The correct answer is: Electromagnets can be made much stronger than permanent magnets. -------------------------------------------------------------------------------- Question 2c of 15 ( 2 Magnets and Compasses 261113 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Which statement is true of magnets? Choice Feedback A. A magnet always has a north pole, and may or may not also have a south pole. Magnets always have two poles. B. Electromagnets are generally weaker than permanent magnets. Electromagnets can actually be much stronger than permanent magnets. *C. Earth is an electromagnet. That's correct! D. Permanent magnets can be turned off. Permanent magnets cannot be turned off. Global Incorrect Feedback The correct answer is: Earth is an electromagnet. -------------------------------------------------------------------------------- Question 3a of 15 ( 3 Characteristics of Earth's Layers 166227 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Why is the inner core a solid, even though it has a higher temperature than the outer core, which is a liquid? Choice Feedback A. The inner core is more easily deformed than the outer core. This is not true. The inner core is a solid, whereas the outer core is a liquid. B. The inner core contains mostly silicon. This is not true. The inner core contains mostly iron and some nickel. *C. The inner core is under more pressure than the outer core. That's correct! D. The inner core is under less pressure than the outer core. The amount of pressure increases with depth. Global Incorrect Feedback The correct answer is: The inner core is under more pressure than the outer core. -------------------------------------------------------------------------------- Question 3b of 15 ( 3 Characteristics of Earth's Layers 261114 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: What keeps the inner core in a solid state? Choice Feedback A. Low temperature This is not true. The inner core is at a high temperature. B. High temperature This is not true. It is at a high temperature, but this is not what keeps it a solid. *C. High pressure That's correct! D. Low pressure The amount of pressure increases with depth. Global Incorrect Feedback The correct answer is: High pressure. -------------------------------------------------------------------------------- Question 3c of 15 ( 3 Characteristics of Earth's Layers 261116 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: What factor is responsible for keeping the inner core in a solid state? Choice Feedback A. Strong electricity This is not true. B. Strong magnetism This is not true. Magnetism does not cause it to be a solid. *C. High pressure That's correct! D. High temperature This would tend to make it a liquid. Global Incorrect Feedback The correct answer is: High pressure -------------------------------------------------------------------------------- Question 4a of 15 ( 3 Plate Movement 166228 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Why is oceanic crust subducted under continental crust? Choice Feedback A. Oceanic crust is less dense than continental crust. This would mean that continental crust would be subducted instead. *B. Oceanic crust is denser than continental crust. That's correct! C. Oceanic crust is older than continental crust. Continental crust is generally much older than oceanic crust. And age isn't the determining factor in subduction. D. Oceanic crust is moving faster than continental crust. This is not true, and would not matter anyway. The density determines which is subducted. Global Incorrect Feedback The correct answer is: Oceanic crust is denser than continental crust. -------------------------------------------------------------------------------- Question 4b of 15 ( 3 Plate Movement 261118 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Oceanic crust slides under continental crust during subduction because oceanic crust is _______. Choice Feedback A. less dense This would mean that continental crust would be subducted instead. *B. denser That's correct! C. younger Age isn't the determining factor in subduction. D. faster This is not true, and would not matter anyway. Global Incorrect Feedback The correct answer is: denser. -------------------------------------------------------------------------------- Question 4c of 15 ( 3 Plate Movement 261119 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: What happens during subduction? Choice Feedback A. Dense continental crust slides under less dense oceanic crust. Continental crust is less dense than oceanic crust. *B. Dense oceanic crust slides under less dense continental crust. That's correct! C. Dense oceanic crust slides over less dense continental crust. The more dense something is, the more likely it will slide underneath. D. Dense continental crust slides over less dense oceanic crust. The more dense something is, the more likely it will slide underneath. Global Incorrect Feedback The correct answer is: Dense oceanic crust slides under less dense continental crust. -------------------------------------------------------------------------------- Question 5a of 15 ( 3 Characteristics of Earth's Layers 166229 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: What causes the pressure that allows diamonds to form in the mantle? Choice Feedback A. The weight of the rocks in the crust and core The weight of the rocks in the core does not add pressure to the mantle. B. The sun's gravity acting on Earth The sun's gravity does not exert a pressure on the mantle. C. The weight of the rocks in the outer core Pressure is exerted by rocks on top of the mantle. *D. The weight of the rocks in the crust and upper mantle That's correct! Global Incorrect Feedback The correct answer is: The weight of the rocks in the crust and upper mantle. -------------------------------------------------------------------------------- Question 5b of 15 ( 3 Characteristics of Earth's Layers 261120 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: What causes the pressure that allows diamonds to form in the mantle? Choice Feedback A. The moon's tidal forces The moon does not create a pressure in this way. B. Gravity from the sun The sun's gravity does not exert a pressure on the mantle. C. Upward force from rocks in the core Pressure is exerted by rocks on top of the mantle. *D. Downward force from rocks in the crust That's correct! Global Incorrect Feedback The correct answer is: Downward force from rocks in the crust. -------------------------------------------------------------------------------- Question 5c of 15 ( 3 Characteristics of Earth's Layers 261121 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Why can diamonds form in the mantle? Choice Feedback A. The weight of the rocks in the outer core increases the temperature. The weight of the rocks in the core does not affect the mantle. B. The sun and moon cause a low pressure in the upper mantle. The sun and moon do not have this effect. C. The weight of the rocks in the outer core results in high pressure. Pressure is exerted by rocks on top of the mantle. *D. The weight of the rocks above the mantle results in high pressure. That's correct! Global Incorrect Feedback The correct answer is: The weight of the rocks above the mantle results in high pressure. -------------------------------------------------------------------------------- Question 6a of 15 ( 1 Seismic Waves 261769 ) Maximum Attempts: 1 Question Type: Text Fill In Blank Maximum Score: 2 Is Case Sensitive: false Correct Answer: refraction Question: When a seismic wave crosses a boundary, it will change directions in the process of _______. Attempt Incorrect Feedback 1st That's incorrect. Correct Feedback That's correct! Global Incorrect Feedback The correct answer is: refraction. Refraction is the bending of a wave when it reaches a boundary. -------------------------------------------------------------------------------- Question 6b of 15 ( 1 Seismic Waves 261123 ) Maximum Attempts: 1 Question Type: Text Fill In Blank Maximum Score: 2 Is Case Sensitive: false Correct Answer: Reflection Question: What is it called when a seismic wave bounces backward when it reaches a boundary? Attempt Incorrect Feedback 1st That's incorrect. Correct Feedback That's correct! Global Incorrect Feedback The correct answer is: Reflection Reflection is the bouncing back of a wave when it reaches a boundary. -------------------------------------------------------------------------------- Question 6c of 15 ( 1 Seismic Waves 261126 ) Maximum Attempts: 1 Question Type: Text Fill In Blank Maximum Score: 2 Is Case Sensitive: false Correct Answer: Absorption Question: _______ is when a wave's energy is lost to a surface, making the wave weaker. Attempt Incorrect Feedback 1st That's incorrect. Correct Feedback That's correct! Global Incorrect Feedback The correct answer is: Absorption. Absorption is when the energy of a wave is absorbed by a surface, making the wave weaker. -------------------------------------------------------------------------------- Question 7a of 15 ( 1 Poles 166231 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: About how often do Earth's magnetic poles reverse? Choice Feedback A. Every billion years They reverse much more frequently than that. B. Every 100 million years They reverse much more frequently than that. *C. Every 250,000 years That's correct! D. Every 22 years The sun's magnetic pole reverses this often. Global Incorrect Feedback The correct answer is: Every 250,000 years. -------------------------------------------------------------------------------- Question 7b of 15 ( 1 Poles 261130 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Earth's magnetic poles reverse approximately every ______ years? Choice Feedback A. billion They reverse much more frequently than that. B. 10 million They reverse much more frequently than that. *C. 250,000 That's correct! D. 22 The sun's magnetic pole reverses this often. Global Incorrect Feedback The correct answer is: 250,000. -------------------------------------------------------------------------------- Question 7c of 15 ( 1 Poles 261131 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: About how often does the sun have a pole reversal? Choice Feedback A. Every billion years It reverses much more frequently than that. B. Every 100 million years It reverses much more frequently than that. *C. Every 22 years That's correct! D. Every 250,000 years Earth's magnetic pole reverses this often. Global Incorrect Feedback The correct answer is: Every 22 years. -------------------------------------------------------------------------------- Question 8a of 15 ( 2 Earth's Mechanical Layers 338173 ) Maximum Attempts: 1 Question Type: Matching II Maximum Score: 2 Question: Match the layer of Earth with its characteristic. Choice Text Correct Match Match Text A. Crust D. Hottest part of Earth B. Mantle C. Creates Earth's magnetic field C. Outer core A. Upper section of the lithosphere D. Inner core B. Makes up the asthenosphere Attempt Incorrect Feedback 1st That's incorrect. Correct Feedback That's correct! Global Incorrect Feedback The correct answers are: Crust: Upper section of the lithosphere Outer core: Creates Earth's magnetic field Mantle: Makes up the asthenosphere Inner core: Hottest part of Earth The crust makes up the upper section of the lithosphere. The asthenosphere is composed of material in the mantle. The outer core creates Earth's magnetic field, and the inner core is the hottest part of Earth. -------------------------------------------------------------------------------- Question 8b of 15 ( 2 Earth's Mechanical Layers 338174 ) Maximum Attempts: 1 Question Type: Matching II Maximum Score: 2 Question: Match the layer of Earth with its characteristic. Choice Text Correct Match Match Text A. Lithosphere D. Creates Earth's magnetic field B. Asthenosphere C. Contains the lower mantle C. Mesosphere A. Contains the crust D. Core B. Most deformable layer Attempt Incorrect Feedback 1st That's incorrect. Correct Feedback That's correct! Global Incorrect Feedback The correct answers are: Lithosphere: Contains the crust Asthenosphere: Most deformable layer Mesosphere: Contains the lower mantle Core: Creates Earth's magnetic field The crust makes up the upper section of the lithosphere. The asthenosphere is composed of material in the mantle. The mesosphere contains most of the lower mantle. The core creates Earth's magnetic field. -------------------------------------------------------------------------------- Question 8c of 15 ( 2 Earth's Mechanical Layers 338175 ) Maximum Attempts: 1 Question Type: Matching II Maximum Score: 2 Question: Match the layer of Earth with its characteristic. Choice Text Correct Match Match Text A. Lithosphere D. Hottest layer B. Asthenosphere C. Contains the lower mantle C. Mesosphere A. Contains the tectonic plates D. Core B. Drives the movement of the plates Attempt Incorrect Feedback 1st That's incorrect. Correct Feedback That's correct! Global Incorrect Feedback The correct answers are: Lithosphere: Contains the tectonic plates Asthenosphere: Drives the movement of the plates Mesosphere: Contains the lower mantle Core: Hottest layer The lithosphere contains the tectonic plates, and. Tthe asthenosphere drives the movement of the plates. The mesosphere contains most of the lower mantle. The core is the hottest layer. -------------------------------------------------------------------------------- Question 9a of 15 ( 2 Earth's Magnetism 166233 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: How is the orientation of Earth's magnetism recorded in rocks on the ocean floor? Choice Feedback A. A rock changes its magnetic orientation when the pole reverses. Once a rock cools, its magnetic orientation does not change. *B. Earth's magnetic orientation is locked into the rock when the rock cools. That's correct! C. All rocks have the same magnetic orientation. The rocks on the seafloor have alternating magnetic orientation, due to pole reversals. D. Rocks align themselves to Earth's gravitational field. Rocks align themselves to the magnetic field, not the gravitational field. Global Incorrect Feedback The correct answer is: Earth's magnetic orientation is locked into the rock when the rock cools. -------------------------------------------------------------------------------- Question 9b of 15 ( 2 Earth's Magnetism 261136 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Why do magnetic stripes appear on the seafloor? Choice Feedback A. Cooled rocks change their magnetic orientation when the pole reverses. Once a rock cools, its magnetic orientation does not change. *B. The seafloor spreads apart, creating new rocks that record magnetic orientation. That's correct! C. Different types of rocks align differently to magnetic fields. This is not the reason. D. Rocks align themselves to Earth's gravitational field. Rocks align themselves to the magnetic field, not the gravitational field. Global Incorrect Feedback The correct answer is: The seafloor spreads apart, creating new rocks that record magnetic orientation. -------------------------------------------------------------------------------- Question 9c of 15 ( 2 Earth's Magnetism 261137 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: How do magnetic stripes show the history of Earth's magnetic field? Choice Feedback A. As you move down through the seafloor, rocks get older. Striping does not occur as you go down. *B. As you move away from an ocean ridge, the rocks get older. That's correct! C. As you move away from a coast, the rocks get younger. This is not where striping originates. D. As you move eastward along a continent, rocks get older. Magnetic stripes occur in ocean crust. Global Incorrect Feedback The correct answer is: As you move away from an ocean ridge, the rocks get older. -------------------------------------------------------------------------------- Question 10a of 15 ( 2 Faults and Boundaries 166234 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: A _____ fault generally occurs at a transform boundary. Choice Feedback *A. strike-slip That's correct! B. normal A normal fault happens at divergent boundaries. C. reverse A reverse fault happens at convergent boundaries. D. thrust This is a type of reverse fault, which happens at convergent boundaries. Global Incorrect Feedback The correct answer is: strike-slip. A strike-slip fault generally occurs at a transform boundary. -------------------------------------------------------------------------------- Question 10b of 15 ( 2 Faults and Boundaries 261138 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: A _____ fault generally occurs at a convergent boundary. Choice Feedback *A. reverse That's correct! B. strike-slip A strike-slip fault happens at transform boundaries. C. normal A normal fault happens at divergent boundaries. D. oblique This does not occur at convergent boundaries. Global Incorrect Feedback The correct answer is: reverse. A reverse fault generally occurs at a convergent boundary. -------------------------------------------------------------------------------- Question 10c of 15 ( 2 Faults and Boundaries 261139 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: A _____ fault generally occurs at a divergent boundary. Choice Feedback *A. normal That's correct! B. reverse A reverse fault happens at convergent boundaries C. strike-slip A strike-slip fault happens at transform boundaries. D. oblique This does not occur at convergent boundaries. Global Incorrect Feedback The correct answer is: strike-slip. A normal fault generally occurs at a divergent boundary. -------------------------------------------------------------------------------- Question 11a of 15 ( 2 Faults and Boundaries 166237 ) Maximum Attempts: 1 Question Type: Text Fill In Blank Maximum Score: 2 Is Case Sensitive: false Correct Answer: normal Question: A _____ fault moves because it is under tension. Attempt Incorrect Feedback 1st That's incorrect. Correct Feedback That's correct! Global Incorrect Feedback The correct answer is: normal. Normal faults are where the two plates pull away from each other. This force is called tension. -------------------------------------------------------------------------------- Question 11b of 15 ( 2 Faults and Boundaries 261141 ) Maximum Attempts: 1 Question Type: Text Fill In Blank Maximum Score: 2 Is Case Sensitive: false Correct Answer: reverse, thrust Question: A _____ fault moves because it is under compression. Attempt Incorrect Feedback 1st That's incorrect. Correct Feedback That's correct! Global Incorrect Feedback The correct answer is: reverse. Reverse faults are where the two plates push toward each other. This force is called compression. Another type of compression fault is a thrust fault. -------------------------------------------------------------------------------- Question 11c of 15 ( 2 Faults and Boundaries 261145 ) Maximum Attempts: 1 Question Type: Text Fill In Blank Maximum Score: 2 Is Case Sensitive: false Correct Answer: strike-slip, strike slip Question: A _____ fault has a shearing force. Attempt Incorrect Feedback 1st That's incorrect. Correct Feedback That's correct! Global Incorrect Feedback The correct answer is: strike-slip Strike-slip faults are where the two plates grind past each other. This force is called shearing. -------------------------------------------------------------------------------- Question 12a of 15 ( 2 Poles 166238 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Which statement is true of Earth's poles? Choice Feedback A. Earth's geographic North Pole moves about 10 km each year. Only the magnetic poles move. B. Earth's north magnetic pole is aligned with its geographic North Pole. The magnetic and geographic poles are generally not in the same place. C. Earth's north magnetic pole is aligned with its geographic South Pole. The magnetic and geographic poles are generally not in the same place. *D. Earth's magnetic and geographic poles are generally not in the same place. That's correct! Global Incorrect Feedback The correct answer is: Earth's magnetic and geographic poles are generally not in the same place. -------------------------------------------------------------------------------- Question 12b of 15 ( 2 Poles 261760 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Which statement is true about Earth's poles? Choice Feedback A. Earth's geographic South Pole moves about 10 km each year. Only the magnetic poles move. B. Earth's south magnetic pole is aligned with its geographic South Pole. The magnetic and geographic poles are generally not in the same place. C. Magnetic poles are defined by Earth's rotation. This is not true. *D. Geographic poles are defined by Earth's rotation. That's correct! Global Incorrect Feedback The correct answer is: Geographic poles are defined by Earth's rotation. -------------------------------------------------------------------------------- Question 12c of 15 ( 2 Poles 261761 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Which statement is true about Earth's poles? Choice Feedback A. The magnetic poles stay in the same place. The magnetic poles do not stay in the same place. B. The geographic poles both wander. Geographic poles do not wander. C. Only the north magnetic and geographic poles wander. This is not true. *D. Only the magnetic poles wander. That's correct! Global Incorrect Feedback The correct answer is: Only the magnetic poles wander. -------------------------------------------------------------------------------- Question 13a of 15 ( 2 Earth's Crust 166239 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: New crust forms: Choice Feedback A. in an ocean trench. Ocean trenches exist near convergent boundaries, which is where crust is destroyed. B. near a convergent boundary. Convergent boundaries destroy crust through subduction. *C. where two plates pull apart from each other. That's correct! D. at the lithosphere. The lithosphere is the crust. Global Incorrect Feedback The correct answer is: where two plates pull apart from each other. -------------------------------------------------------------------------------- Question 13b of 15 ( 2 Earth's Crust 261762 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: New crust forms: Choice Feedback A. where two plates collide. This is where crust is destroyed. B. near a convergent boundary. Convergent boundaries destroy crust through subduction. *C. at ocean ridges. That's correct! D. at the asthenosphere. The asthenosphere is a layer below the crust. Global Incorrect Feedback The correct answer is: at ocean ridges. -------------------------------------------------------------------------------- Question 13c of 15 ( 2 Earth's Crust 261763 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Crust is destroyed: Choice Feedback A. near ocean ridges. This is where new crust forms. B. near a divergent boundary. Divergent boundaries create crust. *C. near ocean trenches. That's correct! D. at the lithosphere. The lithosphere is the crust. Global Incorrect Feedback The correct answer is: near ocean trenches. -------------------------------------------------------------------------------- Question 14a of 15 ( 2 Plate Movement 166240 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Which was used to dispute continental drift? Choice Feedback *A. The existence of land bridges That's correct! B. Magnetic striping on the ocean floor This is evidence for plate tectonics. C. Mesosaurus fossils This is evidence for plate tectonics. D. Seafloor spreading This is evidence for plate tectonics. Global Incorrect Feedback The correct answer is: The existence of land bridges. -------------------------------------------------------------------------------- Question 14b of 15 ( 2 Plate Movement 261764 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: Which was used to by Wegner to establish continental drift? Choice Feedback *A. Mesosaurus fossils That's correct! B. Rock samples from the mantle He never had this evidence. C. Evidence of tidal forces He never had this evidence. D. The existence of land bridges This was evidence against plate tectonics. Global Incorrect Feedback The correct answer is: Mesosaurus fossils. -------------------------------------------------------------------------------- Question 14c of 15 ( 2 Plate Movement 261765 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: What were land bridges used as an explanation for? Choice Feedback *A. Mesosaurus fossils That's correct! B. Magnetic striping on the ocean floor This was not explained by land bridges. C. Tidal forces This was not explained by land bridges. D. Seafloor spreading This was not explained by land bridges. Global Incorrect Feedback The correct answer is: Mesosaurus fossils. -------------------------------------------------------------------------------- Question 15a of 15 ( 2 Earth's Mechanical Layers 261770 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: What is the mechanical layer of Earth that contains the tectonic plates? Choice Feedback *A. Lithosphere That's correct! B. Crust This is not a mechanical layer. C. Mantle This is not a mechanical layer. D. Asthenosphere This layer is below the tectonic plates. Global Incorrect Feedback The correct answer is: Lithosphere. -------------------------------------------------------------------------------- Question 15b of 15 ( 2 Earth's Mechanical Layers 261766 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: What is the mechanical layer of Earth that is solid rock and moves the least? Choice Feedback *A. Mesosphere That's correct! B. Crust This is not a mechanical layer. C. Lithosphere This layer moves quite a bit. D. Asthenosphere This layer has convection currents. Global Incorrect Feedback The correct answer is: Mesosphere. -------------------------------------------------------------------------------- Question 15c of 15 ( 2 Earth's Mechanical Layers 261767 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 2 Question: What is the mechanical layer of Earth that has the most active convection currents? Choice Feedback *A. Asthenosphere That's correct! B. Crust This is not a mechanical layer. C. Mesosphere This layer does not have active convection currents. D. Lithosphere This is the top layer. Global Incorrect Feedback The correct answer is: Asthenosphere. --------------------------------------------------------------------------------