The white fatty substance present in the central nervous system (CNS) and peripheral nervous system (PNS) that serves to increase the speed of impulse conduction is called

myelin

Explanation:

Myelin insulates the axon which speeds up impulse conduction.

Hope that helps.

it would be the percentage of food eaten by the flock

i remember doing this lab

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.  

read more on -