When you look at the night sky, sometimes there is a full moon and sometimes the moon looks like it’s barely there. why does this happen?

of those who start drinking before they're 15 will develop alcohol dependence

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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