The life cycle of a star depends primarily on its mass with

The life cycle of a star depends primarily on its mass with bigger stars burning their fuel more quickly. For nuclear fusion in stars to begin, the elements must undergo extremely high temperatures and pressures. Elements heavier than hydrogen are scattered throughout the universe when a massive star explodes as a Supernova. All elements heavier than helium  are produced in the core of a red supergiant. The blackbody  spectrum emitted from a star changes as the star's temperature changes.

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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