Final answer:
Plate Tectonics is the geologic theory that states Earth's lithosphere is broken into large pieces that are slowly, but constantly moving.
Step-by-step explanation:
The geologic theory that states that Earth's lithosphere is broken into large pieces that are slowly, but constantly moving is Plate Tectonics. Plate tectonics explains the movement of the Earth's lithosphere by dividing it into several large and small plates that float on the semi-fluid asthenosphere. These plates interact at their boundaries, leading to various geological phenomena such as earthquakes, volcanoes, and the formation of mountains.
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