As the sleep cycles continue, the proportion of rem sleep in each cycle decreases. true or false

A sleep cycle progresses through the stages of non-REM sleep from light to deep sleep, then reverse back from deep sleep to light sleep, ending with time in REM sleep before starting over in light sleep again.

The statement that as the sleep cycles continue, the proportion of REM (Rapid Eye Movement) sleep in each cycle decreases is false. The sleep cycle has five stages: stages 1-4 and the REM (rapid eye motion) sleep stage.

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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it's c. (to reduce the greenhouse effect/carbon gasses)