Select ALL the correct answers. Which statements are true regarding an energy pyramid?
The number of producers is greater than the number of primary consumers.
The amount of energy at the primary consumer level is greater than the amount of energy at the
secondary consumer level.
The number of primary consumers is less than the number of secondary consumers.
The amount of energy at the producer level is less than the amount of energy at the primary
consumer level.

answer; i believe the answer is hydraulic action;

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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