In a food pyramid, there is typically less biomass at the top (i. e., there are very few individual tertiary consumers, whereas there are numerous individual producers). In three to five sentences, explain this phenomenon, citing evidence relating to energy flow and how plants support ecosystems.

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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