1.Chromosomes play a major role in variation because they 2.The primary effect of a genetic mutation is to

they are bestfriends that is the role in the story that i read my teacher helped me out so i know the answer

Explanation:

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.  

read more on -