Smithsonian Earth's Dynamic Systems

What is the main cause of earthquakes?

• large ocean waves called tsunamis

• movement of tectonic plates

• erosion of topsoil by rivers

• animals burrowing underground

The early hypothesis of ___ was based on observations that suggested continents were once join together, Later, the theory of ___ explained why large pieces of Earth's surface move around and how many of Earth's feathers form.

• plate tectonics; gravitational force

• gravitation force; continental drift

• plate tectonics; continental drift

• continental drift; plate tectonics

In the Earth's mantle, heat is transferred in large convection currents. Within these currents;

• cooler and hotter rock rise but do not sink

• hotter rock rises and hotter rock sinks

• hotter rock rises and cooler rock sinks

• hotter and cooler rock sink but do not rise

Which of the following statements is true?

• The Earth's lithosphere is made up of tectonic plates.

• The Earth's mantle is made up of continents.

• The Earth's mantle is made up of tectonic plates.

• The Earth's lithosphere is entirely made up of liquid magma.

Layers of sand and other sediment that become sediment rock

• always contain the remains of both plants and animals.

• can contain the remains of animals but not plants.

• can contain the remains of plants, animals or both.

• can contain the remains of plants but not animals.

Which of the following lists Earth's compositional layers starting with Earth's center and ending with the outermost layer.

• mantle, crust, core

• crust, mantle, core

• crust, core, mantle

• core, mantle, crust.

How do volcanic mountains form?

• Lava, ash and other materials from volcanic eruptions gradually build up over time.

• Volcanic mountains form below the surface then rise above the surface during earthquakes.

• Running water deposits sediments that builds up to form the mountains over time.

• Tectonic forces squeeze rocks together as two continental plates collide.

The images show how Earth's continents looked 250 million years ago and how they look today. The change in the continents' positions is explained by the modern theory of plate tectonics.

The theory of plate tectonics developed in part from an earlier hypothesis about how continents move. What is the name of this earlier hypothesis?

• natural selection

• earthquake development

• evolution

• continental drift

The Earth's surface is divided up into several large movable tectonic plates. Which of the following is true about these plates?

• The Earth has only continental tectonic plates.

• The Earth has both continental and oceanic tectonic plates.

• The Earth has only oceanic tectonic plates.

• The Earth has neither continental nor oceanic

The tectonic plates float on the 

• lithosphere
• lower mantle
• outer core
• asthenosphere