Plate Tectonics

According to Wegener’s hypothesis of continental drift,

• Earth’s surface is made up of seven major landmasses.

• the continents do not move.

• Earth is slowly cooling and shrinking.

• the continents were once joined together in a single landmass.

Wegener noticed that mountain ranges on the continents of South America and _____________________ line up.

• North America

• Asia

• Africa

• Australia

What is Pangaea?

• the name of a German scientist

• the name of the supercontinent that existed millions of years ago

• another name for continental drift

• the name of an ancient fossil

As a continent moves towards the equator, its climate gets

• icier

• colder

• warmer

• doesn't change

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

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

• along mid-ocean ridges.

• in deep-ocean trenches.

• in deep-ocean trenches.

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

• hot.

• moving toward a deep-ocean trench.

• cool.

• closer to the mid-ocean ridge.

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

• conductioin

• earthquakes

• convection currents in the mantle

• Earth's magnetic field

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

• subduction

• plate tectonics

• deep-ocean trenches

• sea-floor spreading

A place where two plates slip past each other, moving in opposite directions, is known as a

• transform boundary

• divergent boundary.

• convergent boundary.

• rift valley.

Which process adds more crust to the ocean floor?

• suction

• sea-floor spreading

• subduction

• magnetic stripe