The action potential on a motor neuron lasts about 1.5 ms. A large motor neuron conducts the action potential at about 100 m s-1. A. Calculate the distance between the beginning of the action potential and its end during its conduction down the fiber. (At any time, the action potential is located in a place on the neuron; because the action potential does not occur instantaneously, it must be spread out in space.

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.

igneous rocks are formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks.  

the composition depends on the source magma. there are almost a thousand types of composition found till now.  

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