Fill in the missing letters in the paragraph.
The number of underlines shows how many letters you need to fill in. You may answer with the full word or only the missing part.
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The Earth's outer shell is divided into massive slabs of rock known as tectonic plates. These plates are in constant mo_ _ _ _ , though the movement is usually too slow to no_ _ _ _ in daily life. Over long per_ _ _ _ , however, their gradual displacement reshapes the planet’s surface. When plates collide, they form mountain ranges or triggering earthquakes. In other regions, plates move apart, allowing molten material to rise and create new cr_ _ _ . Because the Earth’s surface is always shifting, geological features that appear stable are, i_ fact, never truly sta_ _ _ . This continual mov_ _ _ _ _ reflects the dyn_ _ _ _ nature of plate tec_ _ _ _ _ _ _.