Which of the following is not a distinguishing characteristic of prokaryotic cells? a) their dna is not enclosed within a membrane. b) they lack membrane-enclosed organelles. c) they have cell walls containing peptidoglycan. d) their dna is not associated with histones. e) they lack a plasma membrane.

The answer is:

E. They lack a plasma membrane.

The reason is that the plasma membrane is actually a very important part of their cell. Hope that helps! :)

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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