Define the drift velocity in a conductor

The drift velocity is the average velocity that a particle, such as an electron, attains due to an electric field. It can also be referred to as axial drift velocity. In general, an electron will 'rattle around' randomly in a conductor at the Fermi velocity.

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

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it would be c. predictability