Polyp animals that form coral reefs have many unique adaptations for survival. one polyp feature that is detrimental rather than beneficial is
a)
secretions that produce a hard protective skeleton.
b)
the inability to leave the reef and swim after prey.
c)
stinging cells that kill prey and discourage predators.
d)
symbiotic relationships with algae that photosynthesize and feed them.

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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