Exploring the Depths: Sea Floor Spreading

What are mid-ocean ridges?

• Underwater mountain ranges where sea floor spreading occurs

• Deep trenches found in the ocean floor

• Flat areas on the ocean floor made of sediment

• Volcanic islands found in the middle of the ocean

What is magma?

• A type of sediment found on the ocean floor

• Molten rock beneath the Earth's surface

• The water found in the middle of the ocean

• A species of deep-sea creature

What is the theory of plate tectonics?

• The study of ocean currents

• The theory that the Earth's outer shell is divided into several plates that glide over the mantle

• The idea that the Earth is flat

• The process by which mountains are formed

How does sea floor spreading contribute to the age of the oceanic crust?

• It makes the oceanic crust uniformly old

• It causes the oceanic crust near the mid-ocean ridges to be younger than the crust farther away

• It has no effect on the age of the oceanic crust

• It makes the oceanic crust near the coastlines younger than the crust farther out to sea

What is the lithosphere?

• The uppermost part of the mantle and the crust

• The layer of the earth between the crust and the core

• The outermost layer of the Earth's atmosphere

• The liquid layer of the Earth's core

What is the role of convection currents in plate tectonics?

• They cause the Earth's magnetic field to fluctuate

• They cause the Earth's plates to move

• They cause the Earth's crust to cool down

• They have no role in plate tectonics