<span> The Sun if the object in the solar system that is always one foci. It is also the source of radiation energy which radiates throughout the system. Sun is the only natural source of energy that has helped the growth of life on the planet earth. Without sunlight, life would never have begun on earth.</span>
<span>A coil is used to step up the electric potential difference using the principle of induction.</span>
Then every line segment has one and only one mid-point.
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I think the answer is letter B
It stays constant, because it's using that energy to change state
