Plate tectonics

Heat transfer within a fluid takes place by _______

• convection currents.
• radiation.
• conduction.
• density.

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.

What is Pangaea?

• the name of the supercontinent that existed millions of years ago
• the name of a German scientist
• another name for continental drift
• the name of an ancient fossil

Which type of evidence was NOT used by Alfred Wegener to support his continental drift hypothesis?

• evidence from landforms
• evidence from human remains
• evidence from climate
• evidence from plant and animal fossils

Most geologists rejected Alfred Wegener’s idea of continental drift because _______

• they were afraid of a new idea.
• Wegener was interested in what Earth was like millions of years ago.
• Wegener could not identify a force that could move the continents.
• Wegener used several different types of evidence to support his hypothesis.

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

• along mid-ocean ridges.
• in deep-ocean trenches.
• at the north and south poles.
• along the edges of all the continents.

How did scientists discover that rocks farther away from the mid-ocean ridge were older than those near it?

• by determining the age of rock samples obtained by drilling on the sea floor
• by observing eruptions of molten material on the sea floor
• by mapping rocks on the sea floor using sonar
• by measuring how fast sea-floor spreading occurs

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

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

• conduction.
• convection currents in the mantle.
• earthquakes.
• Earth’s magnetic field.

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

• subduction
• plate tectonics
• deep-ocean trenches
• sea-floor spreading