Final answer:
Tectonic plates are the subject of this question, as they are in constant motion and change the forms of the Earth's crust. This movement can result in earthquakes, volcanic eruptions, and the formation of mountains.
Step-by-step explanation:
Tectonic Plates
Tectonic plates are in constant motion and change the forms of the Earth's crust. These plates are large pieces of the Earth's lithosphere that fit together like a jigsaw puzzle, covering the entire surface of the Earth. The movement of tectonic plates can result in various geological phenomena such as earthquakes, volcanic eruptions, and the formation of mountains.
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