Final answer:
The outer layer of Earth's crust is made up of huge pieces of rock called tectonic plates. They are large sections of the Earth's lithosphere that move and cause geological phenomena such as earthquakes and volcanic eruptions.
Step-by-step explanation:
The outer layer of Earth's crust is made up of huge pieces of rock called tectonic plates. Tectonic plates are large sections of the Earth's lithosphere that fit together like a puzzle, covering the Earth's surface. These plates float on the semi-fluid asthenosphere below them and move very slowly, causing various geological phenomena such as earthquakes and volcanic eruptions.
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