How does thermal energy transfer when a room is heated by a furnace?
a. hot air is absorbed by the objects in the room; cold air expands and rises
b. hot air is circulated through the room; the hot air rises, cold air falls
c. hot air makes direct physical contact with the objects in the room and rises
d. hot air is transmitted by electromagnetic waves; the hot air rises and falls

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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dz nuts.   eeneneneeenenne

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

since there are no options posted i'll give you a few examples.

a dolphin's flipper, bird's wing, cat's leg.