Unit 7 Chapter 9 Quiz

What is the Mid-Atlantic Ridge?

• A deep valley where plates are moving together.

• A long, underwater mountain range where tectonic plates are moving apart.

• A chain of islands formed by volcanic eruptions.

• A wide flat area on the ocean floor.

How do hydrothermal vents form?

• Lava from underwater volcanoes creates steam that rises through cracks.

• Cold seawater sinks through cracks, heats near magma, and returns as hot water.

• Ocean currents carry warm water into deep-sea areas, heating the cracks.

• Geysers on land cause water to boil under the ocean.

Why does the water coming out of hydrothermal vents look like smoke?

• The water is turning into steam.

• The water mixes with lava.

• Minerals in the hot water form tiny particles when they meet cold seawater.

• Bubbles from deep-sea animals create the smoky appearance.

What type of animals might live near hydrothermal vents?

• Sharks and dolphins.

• Pale shrimp, giant tube worms, and white crabs.

• Coral reefs and tropical fish.

• Seagulls and sea turtles.

What did scientists learn about seafloor spreading from the Mid-Atlantic Ridge?

• Tectonic plates move closer together over time.

• Continents are pushed farther apart as the seafloor spreads.

• Underwater volcanoes cause the seafloor to shrink.

• The ocean floor never changes.