Plate tectonics

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

• conduction of the air

• earthquakes and volcanos

• convection currents in the mantle

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

• along the edges of all the continents

• along the mid-ocean ridges

• along the north and south poles

What technology did scientists use to map the mid-ocean ridge?

• sonar

• satellites

• airplanes

When continental plates pull apart at a divergent boundary on land, a _________ forms.

• rift valley

• mountain

• subduction

Along a __________________ boundary, two plates slip past each other, moving in opposite directions.

• divergent

• transform

• convergent

The theory of ______________________ was that all continents were once joined as a single supercontinent and have since drifted apart.

• continental drift

• continental valley

• continental boundary

The geological theory that states pieces of Earth's lithosphere are in constant, slow motion is the theory of ______.

• convergent boundary

• subduction

• plate tectonics

This forms between 2 oceanic plates that are moving apart.

• mountain range

• mid-ocean ridge

• subduction

This forms when 2 plates of different densities collide and one plate goes under the other plate.

• mountain range

• deep-ocean trench

• mid-ocean ridge

When 2 oceanic plates collide....

• one bends and slides under the other forming a trench

• they push the crust up into mountains