Lesson 2: Chapter 9 Plate Tectonics

Multiple Choice

Why was the mapping of the ocean floor after WWII significant for scientific discovery?

• It helped scientists locate enemy submarines only

• It led to the discovery of mountain ranges and mid-ocean ridges under the ocean

• It was used to measure ocean temperature

• It helped scientists find new species of fish

Multiple Choice

Which feature of the seafloor is formed as sediment falls and covers the basalt crust over time, making it appear smooth?

• Abyssal plain

• Mid-ocean ridge

• Oceanic trench

• Continental shelf

Multiple Select

Which of the following statements about Earth's magnetic field are correct?

• It is created by the iron-rich liquid outer core.

• Its direction is always constant.

• It can have normal and reversed polarity.

• It has no effect on magnetic minerals in rocks.

Multiple Choice

What did scientists discover about the magnetic stripes on both sides of the mid-ocean ridges?

• Each pair has similar composition, age, and magnetic character.

• They are randomly distributed.

• They only appear on one side of the ridge.

• They are formed by sediment deposition.

Multiple Choice

According to the diagram, what happens to the age of rocks as you move farther away from the mid-ocean ridge?

• Rocks get older.

• Rocks get younger.

• Rock age remains the same.

• Rock age fluctuates randomly.

Multiple Choice

How did the development of echo sounders after WWII contribute to the exploration and mapping of the ocean floor?

• They helped scientists locate enemy submarines and measure the depth of the ocean floor.

• They were used to detect marine life and study ocean currents.

• They allowed scientists to collect water samples from deep ocean trenches.

• They helped scientists predict volcanic eruptions under the sea.