Carbon dioxide taken in by plants is used to produce which of these?
a. simple sugars
b. proteins
c. nucleic acids
d. lipids

they float because they are less dense than the water itself

something denser than water, like a rock, will sink to the bottom

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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