science

Most geologists think that the movement of Earth’s plates is caused by

• conduction.

• earthquakes

• convection currents in the mantle.

• Earth’s magnetic field.

According to the theory of plate tectonics, which layer of the earth is broken into separate sections called plates?

• continental crust

• oceanic crust

• lithosphere

• asthenosphere

In sea-floor spreading, molten material rises from the mantle and erupts

• along the edges of all the continents

• at the north and south poles

• along mid-ocean ridges

• In deep ocean trenches

A collision between two pieces of continental crust at a converging boundary produces a

• mountain range

• mid-ocean ridge

• Rift Valley

• deep ocean trench

The process by which the ocean floor sinks beneath a deep ocean trench and back into the mantle is known as

• convection

• continental drift

• subduction

• conduction

The place where two plates come together is known as a

• convergent boundary

• transform boundary

• divergent boundary

• Rift Valley

Where does a rift valley form?

• convergent plate boundary

• divergent plate boundary

• transform plate boundary

• deep ocean trench

a place where two plates move away from each other is known as a

• convergent boundary

• transform boundary

• continental drift

• divergent boundary

Which of the following statements about mid-ocean ridges is true?

• mid-ocean ridges are always near the water's surface

• mid-ocean ridges can be longer than the Rockies and Andres Mountains

• Mid ocean ridges were first discovered using GPS

• Mid-ocean ridges have a flat plateau at their highest point

Old oceanic crust is more dense than new oceanic crust because it is

• hot

• cool

• moving toward a deep-ocean trench

• closer to the mid-ocean ridge