How can pesticide use be harmful to human agriculture? a.
The loss of beneficial microfauna can reduce soil productivity.
b.
Pesticides eliminate harmful insect pests.
c.
Pesticides target the elimination of beneficial soil microflora.
d.
The use of pesticides kills all soil microflora and microfauna

I'm going wit number a

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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thinking it would be physical characteristics