"which activity could lead to carbon monoxide poisoning? "

Teak surfing is an activity that could lead to carbon monoxide poisoning. It is a water sport (illegal) wherein the person holds onto any part of a powerboat (such as the swim platform, swim deck, swim step, or swim ladder) while being dragged through the water. The boat may create a suction behind it and can trap exhaust fumes behind the boat, which can cause carbon monoxide poisoning to the person holding on to the boat.

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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