Review Unit Test: Earth's Surface and Structure

How do the Earth's continental and ocean crust compare in density?

• A. Continental crust is less dense than oceanic crust.
• B. Oceanic crust and continental crust have the same density.
• C. Oceanic crust is less dense than continental crust.
• D. Continental crust has a high density, while oceanic crust has no density.

At the bottom of the ocean, a long ridge of rock has formed at the boundary between two tectonic plates. The rock close to the ridge is younger than rock that is farther away. What type of motion would best explain this ridge?

• one plate moving under the other
• two plates pushing together
• one plate sliding past the other
• two plates moving apart

Chrystal made a table to help her remember a few properties of igneous rock and sedimentary rock. A broken pen leaked ink on her paper. Her table is shown below. What are igneous rock and sedimentary rock made from?

• A. Igneous rock is made from dead organisms, and sedimentary rock is made from non-recycled plastic.
• B. Igneous rock is made from cooled lava, and sedimentary rock is made from non-recycled plastic.
• C. Igneous rock is made from dead organisms, and sedimentary rock is made from layers of rock particles.
• D. Igneous rock is made from cooled lava, and sedimentary rock is made from layers of rock particles.

When rock forms, surfaces of land can change. The image below shows lava from an active volcano moving through a forest. As the lava carves out the surface of the land, what type of rock will it form as it cools?

• A. Metamorphic
• B. Fossilized
• C. Sedimentary
• D. Igneous

Which of the following natural processes takes the longest to occur?

• A. plates colliding to form a mountain range
• B. a volcano erupting
• C. lightning striking a tree
• D. a molecule of water moving through the water cycle

When two tectonic plates are in contact, several events are possible. Sometimes, two plates that are in contact with each other push in opposite directions. Forces can build up until there is a sudden movement of both plates as shown below. What is the result of this sudden movement?

• A. Chemical Weathering
• B. A volcanic eruption
• C. An Earthquake
• D. Mountain Building

If old mountains wear down over the course of millions of years, what is one of the primary reasons that mountains still exist?

• A. New mountains are created through city development.
• B. New mountains are created through tectonic and volcanic activity.
• C. New mountains are created from decomposition of trees.
• D. New mountains are created from leaf litter.

A divergent plate boundary is a boundary at which two tectonic plates move away from each other. As the plates move apart, magma rises upward between them and erupts onto the ocean floor as lava. This lava cools quickly to form solid rock. Over time, these hardened lava flows build up on top of each other and are uplifted by tectonic forces to form mid-ocean ridges. Based on this information, what type of rock are mid-ocean ridges made of?

• A. igneous rock
• B. sedimentary rock
• C. metamorphic rock
• D. fossilized rock

The layer of the Earth called the mantle is often described as convecting. In this context, convection is

• A. a process that occurs on the Earth's surface.
• B. a process that keeps the mantle stationary.
• C. a continuous cycle in the Earth's interior.
• D. a step in the formation of sedimentary rock.

The image below shows what occurs under Earth's surface in certain areas. What does the model demonstrate?

• A. Tectonic plates are pushed apart partly due to convection currents moving through the asthenosphere.
• B. In the asthenosphere, as heat circulates, plates are pushed upward causing seismic activity.
• C. Tectonic plates are pushed apart due to steam caused by heat circulation in the asthenosphere.
• D. In the asthenosphere, circulating heat expands the thickness of the crust of each plate.