What are the reactants for photosynthesis? C6 H12 06, 6 02
O 6 H20, 6 CO2, Light energy
chlorophyll, plant, sunlight
none of the above

thymine. in rna, thymine is replace by uracil

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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nucleus

would be most reasonable answer tbh