Plate Tectonics and Seafloor Spreading Review

Which of the following causes Earth's tectonic plates to move?

• Energy from the Sun

• Magnetic Pole Reversal

• Convection currents in the mantle

• Faults in Mountain Ranges

Answer explanation

Convection currents in the mantle are caused by the heat from Earth's core, creating movement in the semi-fluid mantle. This movement drives the tectonic plates above, causing them to shift and interact.

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NGSS.MS-ESS2-3

The type of plate boundary where two plates come together is a .....

• Convergent Boundary

• Divergent Boundary

• Transform Boundary

• Plate Boundary

Answer explanation

The correct answer is 'Convergent Boundary' because it describes the type of plate boundary where two tectonic plates collide or come together, leading to geological features like mountains or subduction zones.

A divergent boundary occurs when plates ....

• Pull apart

• Come together

• Slide past each other

• subducting

Answer explanation

A divergent boundary occurs when tectonic plates pull apart from each other. This movement creates new crust as magma rises to the surface, distinguishing it from other boundary types where plates come together or slide past each other.

The area where two tectonic plates meet.

• mantle

• focus

• plate boundary

• convection

Answer explanation

The area where two tectonic plates meet is called a plate boundary. This is where interactions such as earthquakes and volcanic activity often occur, distinguishing it from other terms like mantle or focus.

This landform can occur at a divergent plate boundary.

• ocean trench

• mid-ocean ridge

• tall mountains

• transform fault

Answer explanation

A mid-ocean ridge forms at divergent plate boundaries where tectonic plates move apart, allowing magma to rise and create new oceanic crust. This is distinct from ocean trenches, tall mountains, and transform faults.

Which of the following objects best represents the movement that occurs during sea-floor spreading?

• Elevator

• Conveyor belt

• Rollercoaster

• Hot air balloon

Answer explanation

The conveyor belt best represents sea-floor spreading as it illustrates the continuous movement of tectonic plates away from each other, similar to how a conveyor belt moves materials in opposite directions.

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NGSS.MS-ESS2-1

Wegener’s theory that all continents had once been joined together in a single landmass and have drifted apart since.

• Seafloor Spreading

• Continental Drift

• Subduction

• Pangaea

Answer explanation

Wegener's theory of 'Continental Drift' posits that all continents were once part of a single landmass and have since moved apart. This distinguishes it from concepts like Seafloor Spreading and Subduction.

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NGSS.MS-ESS2-2

The formation of new areas of oceanic crust, which occurs through the upwelling of magma at midocean ridges and its subsequent outward movement on either side is called

• Subduction

• Seafloor Spreading

• Divergent boundary

• Convergent boundary

Answer explanation

Seafloor spreading is the process where new oceanic crust forms at midocean ridges as magma rises and pushes outward, creating new seafloor. This distinguishes it from subduction and boundary types.

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NGSS.MS-ESS2-1

NGSS.MS-ESS2-2

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Earth’s plates are in slow, constant motion, driven by convection currents in the mantle

• Theory of Plate Tectonics

• Law of Conservation of Crust

• Law of Conservation of Mass

• Theory of Gravitational Pull

Answer explanation

The Theory of Plate Tectonics explains that Earth's plates move due to convection currents in the mantle, making it the correct choice. The other options do not relate to the movement of tectonic plates.

Tags

NGSS.MS-ESS2-3

The place where old crust is pushed down into a trench is called what?

• subduction

• convection current

• deep-ocean trench

Answer explanation

The process where old crust is pushed down into a trench is called subduction. This occurs at convergent plate boundaries, where one tectonic plate moves under another, leading to geological features like deep-ocean trenches.

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NGSS.MS-ESS2-2

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