3. Assuming you exhale through your nose, list the pathway a molecule of CO2 would follow as it diffuses from a muscle fiber into the blood and is exhaled from the body. List all structures of the circulatory and respiratory systems, including the types of blood vessels, the CO2 molecule would pass through. (Excluding values)

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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links? do you have a link? i don't see anything?

a = executive branch; b = judicial branch