3 Written Questions
3 Multiple Choice Questions
- deep underwater canyons
- In a process taking tens of millions of years, part of the ocean floor sinks back into the mantle at deep-ocean trenches.
- Several types of evidence supported the theory of sea floor spreading: eruptions of molten material, magnetic stripes in the rock of the ocean floor, and the ages of the rocks themselves.
2 True/False Questions
sonar → a device that bounces sound waves off underwater objects and then records the echoes of these sound waves.
mid-ocean ridge → deep underwater canyons