Recent evidence from polar ice core analysis shows that, until now, carbon dioxide levels have never exceeded ppm in the last several hundred thousand years.

Scientists have been doing several experimentation and discovery of the changes of the ice on the pole. Recent evidence from polar ice core analysis shows that, until now, carbon dioxide levels have never exceeded 300 ppm in the last several hundred thousand years.

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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within 30 of the equator hope this