They are equally fast.
Because if given a chance, the person who covered 10m in 5 secs will do the same as th eone who took 10 secs to cover 20m.
together with the crust, we call it the lithosphere. below the lithosphere is a layer of upper mantle called the asthenosphere. this is made up rock that is fluid and can move. it is this fluidity that powers the movement of the tectonic plates of the earth's crust.
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